Bokura Wa Minna Kawaisou (although romance one of the most funny anime ever)
Boku Wa Tomodachi S1&S2 (like the characters, some of S2 have to be skipped)

Usagi drop
the ultimative "tränendrücker", sry, found no appropiate english translation, a little bit older but nothing compares to that

Masamune Kun No Revenge
I love it