In it's stock configuration, the X-box is capable of running "most" of it's games in progressive scan mode, as stated before, with a few game's inexplicably being completely unable to run in progressive scan mode.

As far as DVD playback, I am not entirely sure why, but this mode has been limited to interlaced playback only.

Having said all of this, if you are the risk-taking type, have some electronics background and have an X-BOX that was made prior to September 2002, then you can get a $50 mod chip and install it in your X-BOX, like mine, and it will let you set the systems parameters so that you CAN use it as not only a Progressive DVD player, but also a Region Free DVD player, and also allow you the neat little skill of copying all of your games onto the X-Box hard drive (that is to say after you have upgraded it to something like a 120GB drive)! Now this isn't at all for the light of heart or non-technically minded individuals, but it does allow you to use the system in ways it truely was never intended. I even have a Linux operating system up and operational on the sucker,(take that Mr. Gates!! , as well as running multiple arcade emulators and home concole emulators. It is truely cool to play games like Galaga, Street Fighter 2 and F-Zero in 480 progressive!