Toradora! aired last season, but it has become quite popular in many anime circles, and now I see why.
The basic premise is that of a standard high school romance/comedy, but Toradora! takes the very familiar tropes and change sup the formula just enough to shake off the atmosphere of cliche. It also seems to develop much more quickly than most series in this genre. Top notch animation and compelling characters don't hurt Toradora! either.
If you've enjoyed series like School Rumble and Ouran High School Host Club, then Toradora! is definitely worth checking out.