360's a very good bet although you'll want to wait after the price of the premium drops because of the Elite - another MS tomfoolery that costs them more than they actually get. 360 will definitely get very good support all through its life although the variety of games is fewer than Wii (way much bigger than Xbox though).
Wii - good luck finding it. Currently, with the path it's going - it's set to be the successor of PS2 (console-wise) and DS (overall). The Wii will be your best bet for finding all kinds of games eventually.
PS3 - ha...ha...really, not worth it all right now. Wait a few years until pricedrops and there's some pretty good 1st and 2nd party games worth owning. Treat it like the Gamecube or N64 - it will have good games, but not worth owning the first couple of years.
All just opinions based on the current trends of the this gen's consoles.
