When I'm working at gamestop, I always tell people to get an xbox 360 over any of the other ones, but if you are deciding between the ps3 and wii heres somethings to take into consideration.
If you have a family, the wii will most likely allow EVERYONE in your family to play, regardless of age.
The PS3 doesn't have a great library of games yet and most of the ps2 games won't even work on it (you have to buy the 80gb version for backwards compatibility)
The Wii is a lot harder to find.
PS3 is 2-3x expensive (depending on model)
PS3 games are more expensive
Wii has some great titles that were just released
PS3 supports 1080p with HDMI cables, Wii is only 480p
Really I would rate the systems like this: 360, Wii, PS3, but it is all personal preference. Really it depends on what type of games you like. You say you like racing and adventure games, I'd probably pick up the Wii with Zelda and Mario Kart.
Hope this helps a little