I think the Wii is a nice console and everything, but I don't think i would ever own one but I've played it many time's before at my friends house and I just don't see myself owning JUST a Wii (even though I already own a PS3, but if I never did own a PS3 I can't see myself with just the Wii), I mean it's nice the way it is now because I got a PS3 and when I go to my friends house we sometimes play the Wii (haven't played it in a long time though?) so that's why I find it's a good mixture to have the two together, one for casual fun playing time, and another for hardcore crazy action time.
But I also agree with some of you that is saying the PS3 is somewhat both a casual and hardcore console, IMO i find it to be a little more of a hardcore machine, but by the end of 2008 that might change a little.
(I don't have much to say about the Xbox 360, I don't know much about it, all I know is it's mainly for hardcore players that like FPS's, so that's why I'm saying it's a hardcore machine, I don't know maybe it is somewhat in the category of the PS3 where it's close to the middle of a casual and hardcore gaming machine)