Off the top of my head...
1. Zelda: OoT (N64)
2. Phantasy Star II (Genesis)
3. Y's I and II (Duo)
4. Shenmue (DC)
5. King's Quest IV (PC)
6. Super Metroid (SNES)
7. Gabriel Knight (PC)
8. Castlevania: SotN (PSX)
9. Final Fantasy II (SNES)
10. Final Fantasy Legend (Gameboy)
Runner-ups:
Zelda - any of them, Actraiser (SNES), Phantasy Star IV (Genesis), Final
Fantasy III (SNES), Sim City, Starcraft (PC), Heroes of Might and Magic II
(PC), Might and Magic IV: Clouds of Xeen (PC), Street Fighter II (Arcade),
Alex Kidd in Miracle World (SMS), Mario 64 (N64)
I'm sure I've probably missed some biggie but thats off the top of my head.
Chris K.