SNES - Twin Eagle's Street Fighter II: Champion Edition hack (I know it's a hack and not an original, I cheated). I find most of the SNES stuff rather shit since they all use the same crappy platforming or fighting engine.
Mega Drive - Toss up between Lord of the Rings, Top Fighter 2000, and KoF '99.
Famicom - Street Fighter III is nice and Super Sprint is pretty cool (I know that's lame but Tengen still counts)