I have a Samsung 30 inch wide widescreen tv, I was able to play the HD-DVD version of Dukes Of Hazzard on it, the colors were really noticeably better.  I was unable to play it in 1080p though, but was able to in 1080i.  I suspect this is due to the cable.  
I also have a projector, and I use the VGA cord, and apparently that isn't HD, so I will need to research on connecting the 360 via HD, or get an adapter so I can blow my mind with my projector.  
I noticed a reviewer at EBGames.com said that he was pretty sure that Microsoft will redo the 360 and add the HDDVD into it and add a HDMI  cord for the 360, and a fan to keep it cool.   That would not surprise me.