Well, I recently bought an XBOX and I'm compairing it to the PS2 that I also have...
So far, on the XBOX, I've found that the game play is quite nice and quite high res, i love it. I'd rate it above the PS2 in this regaurd.
HOWEVER, you CANNOT use the XBOX as a DVD player straight out of the box, you HAVE to purchase SEPERATELY the DVD Playback Kit...
PS2 as standard can be used as a DVD player, straight out of the box (which I enjoy since all of my movies are DVD's now).
XBOX comes with a networking adapter straight out of the box, yet the PS2 does not. The PS2's network adapter however is quite affordable and still is the only console capable of Everquest.
Both consoles can support Linux, the PS2 however is easier to modify for linux
I'm curious any other pro's and con's you've found?