You should get yourself a premodded XBox. You will thank me later.
I bought one of these:
http://www.friendtech.com/
(don't get the one with the upgraded processor and RAM, just get the base model with the 120 GB hard drive)
It's amazing the stuff you can do with it. Hell, it's worth the price just to be able to stream the internet radio stations through my stereo with a nice interface, not to mention all the emulators for older systems, ripping DVDs and games to the hard drive, running Linux, etc., etc.
Even if you don't get a modded one, I would still recommend an Xbox over the other systems.