Poor
Pocari_Sweat. But worry not,
Last Sinner also stole Last Exile from me and
Darthtabby most of the rest with FMP/School Rumble so you're not alone
Well, let's try to get some other entries going then.
Aria - There, I call shotgun on this fantastic series. I think its valid since Origination came out in 2008 even if a short 3 episode season came out as a bonus for the BR release last year. Aria is the single show that I went to the effort of importing an overseas release for and its always a bit bittersweet moment when I go back and rewatch an episode. It's such a slow paced and relaxed show about exploring everyday situations and has such an endearing cast of characters that you can't but help fall in love with. It always pains me a bit to remember that the show actually has an ending. The episodes go by so peacefully with virtually nothing happening and then reality hits and the show must end and the characters must move on from that comfortable moment in their lives. It feels very melancholic watching it back again nowadays but back when I first saw it I couldn't even grasp the concept of it ending. It felt so serene and you get so caught up in its slow pace that it works as wonderful relaxing tool.
Tamayura is a very good spiritual successor btw, and it manages to recapture much of the same magic.
Clannad - Yes yes, everyone knows this one but I'll have to add it to my list: it's just very special to me. It hit me at exactly the right time on the exact right emotional notes to stick in my memory. The typical Key melodrama and the stereotypical high school coming of age story coupled with the almost flawless KyoAni execution worked wonders for me back then and I still get misty eyed every time I pick it back up. Its also one of the main reasons I initially joined these forums so there's that as well.
Crest/Banner of the Stars - I have yet to find another space opera show that reached the heights this series reached for me. Starship Operators came very very close but I still prefer this one instead. The personal story of Jintho and Lafiel just got me more personally invested in the characters instead of the situations. Its just a shame that we never got more anime-wise and that the novels english language license got lost in the big Tokyopop crash of the early 2000s (along with Full Metal Panic).
There were other shows that came to mind when I was thinking about this (most of them rather obvious even) but I'll leave them for another time if no one brings them up in the meantime.