i have both and i enjoy both, for now i use the ps3 for movies and motorstorm or resistance, but i use the 360 more for its online gaming, gears of war and crackdown, the only real diference is the blue ray and the price, ha ha. of course since the hd-dvd for the 360 is 200 bucks and the new 120g hard drive is going to be like 150, sudenly the ps3 doesnt sound pricey.
but for now i will go with the 360 specially for games and connectivity with you pc, and all that. if not get the wii, is cheap and you will have a lots of fun making your drunk friends play wario ware
oh and by the way i got my 360 on launching and it fed-up so i had to get a new one, i also got the ps3 and the wii at launching and the ps3 was screwing up, (pixelating, cutting the the screen and a bunch of crap, the only one with no problems id the wii, if you go for the ps3 wait for the second gen, or well you can get lucky and get one that actually works perfectly