Wii = dirt cheap toy for kids and the family, and it's pretty awsome for that, plus it's brand name so the kind of thing parents will buy kids, it was always going to win a numbers war.
360 = Came out first, reasonably priced, but does it have endurance? A few "good" games (I say good, not my cup of tea to be honest - it does have Idolmaster and DOA4 however you can only get one over here and the other will never be regonalised, and if it is they'll replace all the j-pop with pop and it wont be worth playing). Also has the advantage of being a media centre.
PS3 = Over engineered with no games yet, and darn expensive. However we have to remember something about this old dog, the west isn't its real market, they have some truely beutiful games being released in Japan that will probably never see the light of day over here (one by leaf and aquaplus that is just delicious.) I think in the long run it'll have endurance, and as much as you all like to declare "victors" in the console "war" number of base units shipped is only one metric. The second more important metric is games shipped.
Now when do you think the last Japanese Dreamcast game was made and released? Hmmm any takers? Well it was 2005, however they did relaunch it in a modest fashion.
Infact this month in another mag, Japanese releases *grabs another mag* there are 13 Nintendo DS games, 18 360 games (my god one is de capo O.O) 12 ps3 games 2 psp games (one is snowT_T) and 22 ps2 games and a gundam game on the Wii
Now those are by no means the only games being released just the number of games that one mag has on it's release list (and no it's not a sony mag it's a bishounen mag.) What I'm getting at is that the real money is made in the long unglamerous tail of games sales. And Japan has a very long tail indeed continuing many years after a console stops it's production run. Mainly becouse then you're allowed to release more dodgy games on the console as the companies get a bit more relaxed about the rules.
Nintendo, bless its cottons, doesn't have much of a tail (except where the gameboy is conscerned), but we will see, it's all about games kids, who can move the most, having the most machines helps but it sure isn't the whole kit and kabudle. It's about howmuch money you can exploit out of those machines.