I would have to vote for Playstation 3 over the Xbox 360 and the Wii. First of all the difference between the Xbox and the Playstation is very minor in my opinion, the differences are that the remote controls layout and that the Xbox requires you to pay to go online. Also I find the Wii a bit difficult and unfun due to the fact of having to move the remote in almost the exact position.
I have to go with the PS3 on this one. It has the best looking games out there. It may be more expensive, but in the long run, you'll pay more with X-Box live. Also it may have less games, but nearly all are exclusive and none suck.
I would say that they have the same games and yes there is a price difference but I go for quality. Also I do not think that there are less games than the Xbox 360