So far I've bought:
Gunstar Heroes
SF2
Super Probotector
Super Bomberman
Mariokart 64
Now out of these, I'd never really heard of Super Probotector or Mariokart 64, so I bought these on the recommendation of others. I wish I hadn't really, since I didn't get on with either that much. Mariokart 64 is good for a laugh with another person on battle mode, but the single player is genuinely shocking (Oh my word the catchup is just silly!). As for Probotector, it's supposed to be the best SNES game ever (according to the reviews) and yet I find it.. dull. Go play Gunstar for a bit then play this and it's just left wanting. Very disappointed and a waste of money for me.
Kinda makes me wonder if they'll do demos on the VC, since at the moment once you've bought something you're stuck with it with no option of try before you buy.