I remember playing Rayman way back then when I bought my ps1 console. This game was kickass.
Its a simple adventure game with quite a few challenges. Now I played Rayman Raving Rabbids for the Wii and it still rocks.

So here's the rundown from my perspective:

Rayman Raving Rabbids - It maintains a nice adventure like game play which is both funny and challenging. Mini games like tossing a cow, sketching, and smacking the crap out of rabbids.

Rayman Raving Rabbids - This is when they began on making it a party game. Playing the game solo isn't fun, its better to do a multiplayer and challenge each other.

Rayman Party TV - This one is pretty cool. The format of this game runs like a tv program with commercials that runs between games. A snowboarding game was introduced into this game to which you can use the wii fits balance board to steer so you get a better feel of the game. But don't expect to be on snowboards, you'll be riding a pig instead (i think it was a pig)

Overall, for all people who has a wii or plans on getting one, Rayman is a pick you can't go wrong with.