Originally 360s could only do 720p/1080i but MSFT patched this into the consoles in December 06 IIRC.
Also, from Xbox.com (http://www.xbox.com/en-US/hardware/xbox360/hdtv.htm)
"The good news is that, unlike TVs, every Xbox 360? supports HD output at resolutions up to 1080p, so there's no...