In general, I'd say that the PS3 has more games and a larger variety of games than the Wii does (unless you count the GameCube games maybe), but Wii does have a few gems that any real player should wanna play as well. Also, if you give them a chance, there aer other franchises except Zelda and Mario worth playing on Wii as well, you just dun hear about them as much since they aren't as famous.
But still, if it were me, I'd buy the PS3 now and wait for the Wii-U release instead. Luckily for me though, I already have both a PS3 and a Wii =)