As the title suggests , this topic is to list those anime series' which you loved in particular/found to be downright exceptional. For me my all time favourites are (in no specific order)

I tend to like anime/manga that invokes an emotional reaction , is good humoured , has good action , a strong story , is emotionally involving , features plot twists and is diverse.
In all cases where appropriate I am referring to all versions/ovas/seasons of each series (anime and manga both)
This is in no particular order.
-escaflowne
-Imperial puppet orchestra
-Reqiuem from the darkness (I avoided this title for a long time assuming based on its name it was a hentai series, upon reading a review on the them anime website I decided to look into it further to find a story packed with just the right dosage of violence and a highly unique visual style that must be seen to be believed.
While the Japanese voice overs work well the dub here is not so good. The art style intriguing as it is cannot disguise animation that is actually not as great as you may be led to believe . The characters and overall storyline also feel too underdeveloped and not all of the individual stories in each episode are entertaining. Most of the plotlines however can be praised for accomplishing quite an impressive amount in a short time, some of these stories are very well written and even offer the occasional twist at the end.As much as the series attracted me with its strengths , the glaring flaws are very apparent , it is obvious that 12 episodes was much too small to fully tell the main story.)I did like though requiem's nihilistic approach to showing mankind at its lowest level and keeping up a consistently strong atmosphere throughout.)
-Speed grapher ( I am highly surprised that I a veteran critic of studio gonzo am enjoying this series so much, the series is hardboiled, hard nosed , has an appealing , tough as nails male lead,combines a fast paced plot with plenty of action and still manages to include a healthy amount punchy dialogue. Speed grapher is just the right length at 24 episodes, grips its viewers attention from the get go and is downright addicting to the point where I managed at all 24 episodes in one sitting . The problems? Few, while the gory action sequences , atmospheric/edgy scenes are well animated, the series is only aesthetically convenient and the animation quality does vary, the character designs are also rather uninteresting and the dubbed version while largely impressive is not perfect and does have some shaky performances ). On occassion speed grapher shows itself to be a little too overthetop to downright silly at times, one episode features a cannibal crystal woman who eats jewels and a group of unconvincing, off colour eccentric transexuals. Though it is the bizzare sex that comes off as the most disdainable. The series does a particularly good job developing its antagonists, even some of the goons but it is the lead villain and his three henchmen that get the best attention and prove that they are far more than one dimensional cutouts, hell I actually almost teared up at the badguys backstory.
-Ruler of Nabari(Though I would have liked more had they adapted more of the source material, had a less angsty story and more than just average animation)

-Manhole
-Portrait of cossette
-Armed librarians
-First squad
-Lament of the lambs
-Canon
-Romeo x juliet
-Koi Kaze
-Boogiepop (While the animation is a disgrace and a disappointment from madhouse and the voice acting is not the best, with ghosts, a mysterious woman, conspiracies , a secret organization, nice character developments , a hidden serial killer, an effective/engrossing soundtrack along with its genuinely creepy and often scary atmosphere and imagery , boogiepop is a must for fans of Lain and in particular the horror mystery genre)

-Bokurano
-Outlaw star
-pluto
-Dr Black Jack (and that goes for Black Jack 21 at that as well which despite its mediocre vocals, poor animation , outdated art was a perfectly paced , well told storyline that didn't waste a moments time, the helpful plot summaries/story thus far were kept brief but still managed to make the show accessible to those who may have missed an episode. Still though for aesthetic reasons I prefer the ova.

-Sentimental journey/Diamond Daydreams/seraphim call (A unique collection of short straight romance/drama stories that avoid the regular trappings of the genre, the first two feature highly nostalgic character designs from the 90's era and the moe art style of that period before that archetype became a wet dream for pedophiles . The moe characters of the 90's, these first two series at the very least managed to look, act, cute, endearing while still coming off as 18+ year old girls, from what I saw the voice actors chosen never tried too hard to sound un-natural/forced , they sounded like adult/adolescent girls should sound rather than little kids which is the norm nowadays , they were placed in situations that I consider (based on what I recall) to be nothing to out of the ordinary or farfetched. True the art and animation aren't great but these are a million times better than some of the nonsense being marketed to anime fans these days. I suppose the issues I had with Seraphim call were that designs were more modernized moe and all three series were pretty weak in the music department. One thing the first two really have going for them is that each episode is pure character study/development which it achieves in such short runtime.

-Emma
-Perfect Blue
-Golden boy (While I could hardly see it going on for 10 volumes or even working when not animated, the 6 episode ova offered just the right amount of childish/toilet humour without outstaying its welcome. I enjoyed the early 90's character designs , ridiculous, juvenile aspects/execution of it and the animation was great for its time. I felt that although the dubbed version is highly outdated and many of the voice actors have improved tremendously since back then, the voice for the lead character, especially when he over-reacts works extremely well) The series takes something that shouldn't be funny like a lewd comedy and turns it into something hysterical, perhaps it is the voice actors, the over-the top nature or the facial expressions but this was hilarious. Even though it can get quite explicit and not safe for work the series is much much too immature to be called offensive. I can't help but feel this somehow inspired aspects of GTO)
-Rose of versaille
-Legend of the galactic heroes
-Ludwig kakumei
-Boys next door
-Garei
-Horou musoko
-Tegami bachi
-Honey and clover ( I feel that this series is actually better than Nana , it targets a more mature audience and presents its relationships in quite a realistic manner. Not a single character was wasted and they are all easy to relate to in addition to being loveable and endearing. The writing is solid and while the drama probably didn't emotionally involve me, it provided the already great characterization with just that extra boost. In my opinion I consider Honey and clover to be more effective as a comedy than a drama, the jokes are funny, don't fall into the regular traps and although the series is a little daunting in terms of length it doesn't ever lag/drag in any way. The anime ending is a bit of an unwelcome twist that will ruffle a few feathers and the animation is only serviceable with the character designs taking some getting used to as well. To create a fair review I have watched 20 out of 38 episodes of the anime and am moving over to the manga, from what I see JC staff have remained very faithful to the original illustrations.The short snippets of the dubbed version coming out soon suggest that it won't be as good as the original cast but then again they all played their roles so well and were fitting to the respective roles they were given ). The art style to me felt near repugnant at first but as I went on I began to view it in a different light, a beautiful mishmash of old and new. I would go as far as saying this series is a female version/answer to Clannad. While reading/watching I felt the same magic I experienced during my introduction to comics and animation for the first time. )
-The boys who stopped time
-Die
-Cruel fairytales
-Dance in vampire bund
-Tokyo magnitude (While the episode with the robot and abnormal cold symptons wasn't very good and was a departure for the series, I have never seen anything quite like this anime before, particularly one with the subject matter it addresses , it also hits a few emotional notes as well.
-Uzumaki
-Planetes
-Anything by Kaori yuki (save for the beginning of angel sanctuary and fairy cube which were boring as hell)
-Gundam (all series bar g gundam and turn a)
-Vampire hunter
-The fallen vampire
-Kurozuka-Black theater
-Top secret revelation
-Daughters of Mnemosyne.
-Needless ( Despite the poor art the series is well animated and by madhouse at that. Its also extremely Gar/Manly to the point of parody. The action is both amusing and over the top to a ridiculous level but it is entertaining however and the voice actors are good enough to disregard the nearly non-existant plot. The first ending sequence deserves special mention. While the series does feature nudity, the fanservice is most apparent in the ending that actually encompasses more fetishes than I can recall. Needless can be considered gurren lagann without the mecha. Some pitfalls the show falls into as some others have noted is varied animation quality but unusually and not a criticism most would use is that Needless' biggest problem is when it pretends to more than it is and tries to be clever by explaining the attacks or throwing in some random motivations/dialogue to fabricate a storyline )
-Texnolyze
-Lain
-Yotsuba
-Strawberry marshmallow ( I found this as well as Yotsuba significantly more cute/amusing/ better illustrated than Azumanga Daioh and while we're on the subject, I don't consider it a LoLicon manga/anime at all as some others seem to believe , if you read/watch it without taking things out of context you realize this. I believe this is precisely how a slice of life comedy should be done, the characters are the type of kids that everyone knew at least one or two of when they were young. The artwork in the manga is of a better standard than that used in the television series and this played a role in how much funnier I found the source material. While the anime features a good Japanese version, even with the actors chosen for the dub and the fact they actually fit the roles save for Nobue all the actors executions were rather poor and came as a disappointment as the trailer made it seem like the dub was actually better.
The animation in the series would best be describe as "does its job" and is serviceable, not much is going on here so a large budget is hardly neccesary. Strawberry marshmallow relies of cuteness, offbeat humor and simplicity rather than awkward teenage boys make fools of themselves which is a refreshing note)
-mpd psycho
-perfect blue
-liar game
-kaishakus works if only for the lolz
-vampire knights
-world embryo
-saki
-east of eden
-Blood
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-Toradora
-Kodomo no Jikan
-Moetan
-alice in heartland
-Sengoku basara
-bitter virgin
-Kurenai
-Umineko
-Moryou no hakko
-Gungrave
-Trigun
-Corpse princess

-Fruits basket
-Bakemongatari (Undoubtedly this series being based on an ongoing set of 400 page books isn't going to translate ideally onto screen , the animation jumps from stylized slide show to near incredible but this series deserves a commendation for being a harem that thus far has developed not only its female characters well but also its male lead, it injects characterization, drama into a genre that is forced or non-existent in this area. The series has offered some unexpected twists and emotional moments managing to juggle humour , drama in an effective/balanced manner.
-The dub of ghost stories
-Kannagi
-Angel sanctuary (not the horrible ova)
-Godchild/Cain
-Higurashi
-Code Geass
-Hellsing (not the gonzo series)
-Deadman wonderland.
-Spiral

-Rozen maiden
-Monster
-20th century boys
-Gunslinger girl.
-Aoi Hana
-Card captor sakura
-Black lagoon
-Bloody monday
-Death note
-Crimson shell
-Pandora hearts
-Hell girl
-Moon phase
-Mazinger
-Canaan
-Tsukihime (manga)
-Melty blood
-Fate/stay night
-Kara no kyokai
-Phantom requiem for the phantom
-Girls bravo
-Magikano
-The later parts of shuffle
-Kanon
-Clannad
-Air
-Code geass
-Chrono crusade.
-X
-Shigofumi
-full metal alchemist (manga)
-Welcome to the NHK
-Negative happy chainsaw edge
-Elfen lied
-Ouran
-Gundam 00
-First Gundam
-Negima
-Sola
-sayonara zetsubou sensei
-School days
-shana
-chobits
-Excel saga
-Dears
-Outlaw star
-Nadesico
-Ah my Goddess
-Rumbling hearts
-Chaos head
-Aishiteruze baby
-Full moon
-Shugo chara
-Casshern

-Ballad of a death God
-The ghibli movies
-Place promised from early days
-h2o footprints in the sand
-Chevalier D'eon.
-Shikabane hime
-Nanoha