DaddyX3 and Strider turned me on to XBMC ( for the other readers, that stands for XBox Media Center)
Having tried it for a few weeks now. I can honestly say, "there's nothing that comes close".
Forget about all the cool little things, like the Movie information that can be set to update upon startup, the Movie Artwork icons, the customizable scripts, or the other unique features, It simply has the best movie playback of any of the Linux apps available. seriously the difference between Antenna TV and High-def.
I have yet to find a format that it won't play. The only drawback Ive been able to find is the lack of iPod support.
I want to suggest using XBMC as the default movie & music player in 2.1,
I think having an all around media center integrated into Ultimate Edition would put us one more step farther ahead of the rest. No it's not terribly difficult to install and setup, but I think Ultimate Edition would be better for having it integrated with the standard install.