I was planning on just keeping my HTPC plugged into the Xbox HDMI in and using the TV function as intended. My bigger concern is how much it will complicate my harmony remote controlling the PC, how well it will control via IR to the PC dongle, and if XBMC on the PC will even be viable through it.
It is the way of life, shit upgrades, we who go the hard way with HTPC know the game. We deal.
I am OTA only, so really I am happy any way I can get the signal out from my HDhomeruns as smoothly as possible, bonus if my win7 can get its interface out to Xbox without too much trouble.
Just gotta keep it wife friendly.
Worst case is the PC stays on its own HDMI in.