My stepdad has a '360, and I must say even though I played Halo 3 on it before he did (shh), I didn't feel very compelled to go back to it once I had finished. I've played a bit of Gears of War on it, but meh, I didn't find it that great.
My PS2 on the other hand, Metal Gear Solid FTW. I also prefer the PlayStation aesthetics over either Xbox consoles. Yeah, I've been a PlayStation fanboy for years and I've only just realised.. *Sigh*
I'm tempted to get a PS3, but it's still too expensive atm.