While I don't like the 360 because of the issues it's had. (The red ring issue was a serious atrocity committed against gamers everywhere and should not have been stood for. Yet countless people rolled over for it.) I do have to respect it's line up of games. The Gears of War franchise looks good and so does Halo. But beyond that, there isn't much else on the 360 I'm interested in that I can't get elsewhere.
Personally, every time I've used the 360 controller I've always found the 360 controller a bit awkward. The triggers feel a bit off to me and the d-pad felt too loose and easy to hit the wrong direction. Perhaps this feeling would go away with more time spent on a 360, but for now I'll take the comfort and precision of the Dualshock, thanks.