I recently invested in a HDMI cord for my xbox 360 mostly due to wire management. So i hooked it up and by doing so i'm not able to adjust any settings except for Contrast Bright, and Backlight when xbox is set on optimal resoulution. I want to know if i should keep those settings or switch back to 1080i, or 720p if someone can tell me witch one is better and to adjust all the settings myself. Also what do the reference levels and HDMI color spaces settings change and witch one is better.

I am using bbudisin settings.

http://www.avsforum.com/avs-vb/showthread.php?t=953475&page=2

Looks great on mine. Hope fully they will work for you. As for other adjustments. I have mine set like this.

TV HDMI black level: Normal
Xbox 360 hdmi black level: Extended or Expanded what ever its called.
Xbox 360 HDMI color space: Source
Xbox 360 resolution: 720p
TV size: Just Scan for 1:1 pixel mapping.

As I said. His settings work for some and not others. Keep in mind it is not technically accurate. But for me it is fine. Not worth getting a small 32 inch tv ISF calibrated for me. If you want to go further. You will have to calibrate it yourself if you do not like his results.