I rented "Pac-Man World 2" for Gamecube, and I unlocked Pac-Attack there
+ the original Pac-Man (also available on VC)
+ Pac-Mania (not available on VC)
+ Ms. Pac-Man (not available on VC).

Besides of the main adventure I liked Pac-Attack the most, because it's a unique puzzle game.
Watch the video and decide for yourself.

Although you can get Pac-Man World 2 very cheap for Gamecube
and you have one big game + four classics for about ten bucks instead of one classic for 8 bucks. (Yeah, you have to unlock them in Pac-Man World 2 but Pac-Man and Pac-Attack are very easy to unlock). I'd try to get Pac-Man World 2.