These have all been mentioned before, but I just want to add my votes too:
- ICO (still one of my all-time favourite games ever)
- Psychonauts (available cheap on Steam, but if you go that way make sure you've got a gamepad for your PC. It's a platformer after all)
- Beyond Good & Evil (again, cheap on Steam. Less essential to have a gamepad but you'll probably be glad if you do)
- Okami (also out for Wii, I've heard)
- Kingdom Hearts 1 & 2 (only if you're into JRPGs)
Shadow of the Colossus is also good but only if you adore boss fights. (I don't, so it frequently drives me to controller-snapping fury. But I still stubbornly want to finish it sometime.)
- ICO (still one of my all-time favourite games ever)
- Psychonauts (available cheap on Steam, but if you go that way make sure you've got a gamepad for your PC. It's a platformer after all)
- Beyond Good & Evil (again, cheap on Steam. Less essential to have a gamepad but you'll probably be glad if you do)
- Okami (also out for Wii, I've heard)
- Kingdom Hearts 1 & 2 (only if you're into JRPGs)
Shadow of the Colossus is also good but only if you adore boss fights. (I don't, so it frequently drives me to controller-snapping fury. But I still stubbornly want to finish it sometime.)