To be the fair the XBOX wipes the arse of the others for online gaming (community and downloadable content). I'd go as far to say its worth the price.
The PS3 is also a great machine. I don't have one but my brother does, and its well built and a nice bit of kit. Good usb support and internet browser.
I purchased a Wii for my son last xmas. Needless to say its now gone, and the 3 year old XBOX is still here. The Wii is woeful, nearly 200 notes for ahem 'next gen' console. Non-HD, Piss poor graphics, lousy IR controllers and a console that cannot play DVDs. Nintendo your having a laugh!
Project Natal looks interesting too.