My fav is Chiyo. But Yotsuba&!(By Kiyohiko too) Is much better!!!! I've never watched the anime(only a bit of episode 1 on YouTube) But the manga rocks.
I love that show!!! Azumanga Daioh rules! (I like Yotsuba&! better though XD) I like Osaka and Tomo best. The characters who aren't that smart and are kinda weird are my type XD Also, I've never watched the whole animation, just read all four mangas.