From what I hear from friends who work in the video game industry, go with the Xbox 360. The PS3's toolset is more difficult for programmers to work with and thus games will not be coming out as quickly and more exclusive titles will end up on the 360 as less difficult equates to lower development costs and higher profits.

I also happen to know that Sony is investigating why the PS3 is not selling as well as they expected and at this point they believe much of the fault lies with the advertising campaigns rather than the feedback they have gotten from developers.

Of course this could all play out differently but there you go..

If you do go for the PS3, you have to buy the expensive one to get the backwards compatibility for the PS2 games.

For what it's worth, I went with the Wii.