Every Smash Bros game >>> any other fighting game, IMO.
As for other games, I actually really enjoyed Injustice: Gods Among Us, I thought that game was really solid
I've dabbled in some SF games, some MvC games, but they never held my interest any. I can't really say what the worst game is, though.
"You lack the requisite spine and testicular fortitude to study under me"
"You do not know the first note of the music that moves me."