Try 'Metroid 2: The Return of Samus'. That's the second best game behind 'Link's Awakening'. After those two, 'Mario and the 6 Golden Coins' is awesome.
Oh, and the other two Zelda games for GameBoy Color 'Oracle of Seasons/Time' are good.
If you have a GameCube, buy the GBA player. GameBoy games can be played on it as well as GBA games. 'Metroid Fusion' on a tv was like a short version of 'Super Metroid'.
I just ordered 'Metroid: Zero Mission' off of e-bay and it'll be here this week. Life is good.