Impossible to judge since the PS3 isn't out yet...
I'm on a wait and see approach with the PS3...
As far as this year goes, I doubt I'll buy a PS3 in 2006, just because Blu-Ray isn't that big of a format yet, so I don't really need a BR Player... There aren't many original games at all coming out for it.. None that I'm really interested in.. The games that are coming out that I want are also out on 360, and I love the 360 controller.
But, i'll definitely buy a PS3 by the time MGS4 comes out, because I have to have that game, and I always buy every system, but I'll probably just get a Wii this year, and buy the PS3 next year.. I may get a new computer this year, too, so that'll take away my PS3 funds.