Running OS X on the Xbox 360 will deffinitly be an option. I may shell out the $299 for the darn thing when it comes out because I know it's potential. There are developer points on the new board as well, leaving modding deffinitly in play.

As for TCP's comments on modding the Xbox being easy, it can be. When I modded my Xbox originally I soldered the wires on board and did not use any mod chips. Due to a firmware upgrade error by an assistant at the time, the TSOP went south and I was dead in the water. Luckly, though, he scrounged up a Chameleon for me to use. I've got a 512kb BIOS (and without possibly increminating myself, I'll let that sit at that) running on it and works well.

Modding Xbox's can be easy, but trust me, mine was not until we got a mod chip to recover with.
MacBook 2GHz Intel Core 2 Duo w/ 2GB DDR2 RAM & 120GB SATA 5400RPM HDD
Canon Rebel XTI
Google Cr-48 Beta Laptop