A slightly unusual manga, in that it's a series of four-panel strips with occasional graphic-novel bits. We follow the adventures of a group of schoolgirls and their teachers through their last three years of school. I watched and greatly enjoyed the anime based on this series a couple of years ago, and had read fan translations of the first few "chapters" of the manga. It's now been commercially translated as a set of four books by a team from ADV (at about a fiver each, which is certainly a lot cheaper than importing the original manga).
I have no complaints about the manga itself -- it's upbeat and hilariously funny, with nicely minimal artwork, and the four-panel structure works nicely in that it allows both short gags and longer stories to be told. ("Calvin and Hobbes" is perhaps a Western example of the style.) The anime is one of my favourite series, and I think the manga's even better in places.
I have some pretty serious beefs with ADV's translation, though. It compares extremely unfavourably to the fan translation I'd previously read -- words and phrases are needlessly Americanised, jokes are completely rewritten (and guys: you're not Kiyohiko Azuma), and cultural references are replaced (English lessons becoming Spanish lessons, for example -- which spoils later jokes). The first two volumes are entirely without glosses or translation notes; the third has an apologetic letter from ADV about the translation style and some rudimentary notes, but continues the transculturation; it's only by the fourth and last volume that the translators have clearly been restrained a bit. Why companies feel the need to do this is entirely beyond me; it completely spoils the feel of the manga in places.
I'll happily recommend "Azumanga Daioh", but I'd strongly suggest buying the original version if you've got the option; ADV's translation is unusually poor. (The ISBN below is the first volume of four.)
ISBN 1413900003.