Probably going to repeat some others but that's becasue they bear repeating.
Eve No Jikan, a 6 ova series about humans' relationships with their robot servants.
Usagi Drop,a slice of life about a guy raising his grandfather's six year old love child and them building their life together as father/daughter.
Bartender,a series of short stories revolving around bars and the people who frequent them.
Sayonara Zetsubo Sensei,off the wall comedy about a melodramatic teacher and his psychotic classroom making fun of societal problems in the weirdest ways possible.
Baka to Test:a great comedy about a group of idiots trying to get a better classroom via battling with their avatars. THough they only really battle in the first two and last two episodes, the middle is comedy and fun.
Hidamari Sketch: 4 girls(6 in season 3) go to art school and that's it. It's also funny as hell, especially Miyaka odd ball lines, and enough lesyay to choke a horse.
Baccano! and Durarara!! are by the same guy and are both wicked fun with very spastic story telling.
Princess Tutu: Starts of kinda as a light and happy magical girl show then starts getting darker as it goes, a nicely complex story and great characters.
Magical Witch Punie-chan: a parody of magic girl shows with great jokes, and in that same vein Bludgeoning Angel Dokura-Chan.
Mawruru Penguin Drum: Currently ongoing at episode 14, an odd show about two brothers trying to keep their sister alive and that's all I'll say becasue any attempt to describe the rest of plot will end in failure,go watch it.