...Prince of Texxis
...sounds like a cross between Shirow and Shinjo Mayu
A, A' - Powerful doomed romance short.
GTO - underneath the craziness and funny faces is a theme of tolerance and understanding.
Ranma 1/2 - classic neverending comedy.
Azumanga Daioh - High school story without gimmicks. Funny as hell, too, in the original Japanese, confusing in translation.
Aa, Megami-sama! - charming combo of gizmos, cute outfits and that warm fuzzy feeling.
I make no case for these being the best or whatever.