Charles Martinet does a whole range of Nintendo voices including Mario, Wario and many more. During E3 Planet GameCube interviewed him. The full interview can be found here.

TYP: So what is your favorite Mario game?

CM: You know, I have to say I really love every single one, ya know?�.Something like Mario Kart is fun just because it is just sheer fun, ya know what I mean? Just pure fun. Mario Golf is just pure fun. But I really enjoy just getting from level-to-level in, ya know, the Mario games, Mario Sunshine and I think that�but it, but it�it's hard!