Most people I've heard on the forums say Lost Levels is good, and I agree, because I also have it for VC (and used to play it when it was included with Mario Allstars for SNES back in the day). It's like Mario 1, but it is hhaarrddd!
I wouldn't even hesitate on getting Paper Mario 64, best game in my opinion out of any wii games even (of course I havent played that many). Still I replayed the game 3 or 4 times and I have only completely beaten 6 games in my life (4 being pokemon lol too addictive) so im not just saying that, it really is that good.