Get the xbox for, if nothing else, the game Halo. There is no console game that even comes close to comparing. Plus, you can play it online at gamespy.com. The neighbors kids around here are constantly hanging around my door waiting for me to get a game of Halo going. Either that or they are using that as an excuse to hang out with my daughter.
The xbox is set to blow the psII out of the water. This reminds me so much of the Navigator/Explorer issue years ago. Everyone was talking about how Navigator was much better, well established, and blah, blah, blah, blah...we all see what happened.
There is no game out there for the xbox, including Halo, that has used up HALF the capabilities of the xbox yet. It will take developers at least a year to come out with games that will begin to use all of the xbox resources. Basically, what it comes down to is that in a year, all of the games for the psII will be obsolete and way inferior to the xbox games. Yes, right now, psII has more games but that will not last.
Just play Halo once or watch someone play it. That is all it will take to convince you.