My picks (with explanations for the ones that I have not seen on anyone's list so far)
1. Legend of Zelda (NES) - You mean I don't have to start all the way over if I switch the console off? Sweet.
2. Legend of Zelda: Ocarina of Time (N64)
3. PTO II (SNES) - I think I've played more hours of this game than the rest of the SNES library combined (which is insane, I know)
4. Goldeneye 007 (N64)
5. Final Fantasy IV (SNES) - The best story line of a FF game to date (IMHO)
6. SimCity (SNES) - That feeling of getting the big two square buildings? Amazing.
7. Tetris (GB) - Don't listen in class young man, play Tetris!
8. Secret of Mana (SNES)
9. Wii Sports (Wii) - The first game I ever saw otherwise well-adjusted attractive women begging to play en masse. Thank you Nintendo!
10. Super Mario Bros 3 (NES)