GTO is an incredible anime, any disagreements will result in my infinite rage and possibly kittens, depending on my mood and how drunk the pet store owner is today. It's a monday, so probably very much so. The dub is also really good, if only because of Steven Jay Blum.

Ouran High School Host Club is also pretty damned decent, mostly because of how funny it is.

Cowboy Bebop is an obvious choice. Dub over sub, too.