I'd go
MLB Power Pros. Then again I think it's the best 3rd party game on any next get system this generation so far. (with CoD4 a close second)
EDIT: Ooooooh EVER.
Then I'll go FF6.
Followed closely by Chrono Trigger and Gemfire.
SNES just ruled the school.
Oh River City Ransom and Super Dodgeball are close too.