The latest news floating around the web is that XviD and Divx playback will be coming to an Xbox near you soon...
It would seem Microsoft have announced at an event in Rotterdam called Mission 360 that there will be a firmware patch coming out in the next few months that will address the lack of support for these very popular video formats.
Also noted was that Microsoft want to release the Xbox 360 in a variety of new colours. Which is all well and good but I feel a little to late as i'm surely not going to go out and buy a new console just for a colour change.
Especially when there are some extremely nice 3rd party cases out there which I feel sure will blow away whatever Microsoft brings out . :)