Depending on what your focus is on, I'd suggest PS3 or the laptop. The Wii is too limited in what you can do with it, and when you like the Sports stuff, you have to buy all those little gadgets like the nunchucks, balance board, wheel, motion plus, and whatnot, too, so it can get really expensive.
If you're more into multimedia, get the PS3, they have awesome games and the whole thing is just, y'know, amazing.
If you play only once in a while and you want to focus on the 'net access and need something to keep you occupied no matter where you are, get the laptop, but make sure the graphic card is good enough to let you play some of the newer games, too.