A while back the team behind the Xbox Media Center on OS X (which we covered a while back) announced that they were forking the Mac version from the main trunk. Now they've decided that the Mac version will be getting a new name: Plex (as in 'cineplex' or 'googleplex'). For those of you haven't tried it yet, basically Plex is a Front Row replacement media center application that grew out of the long developed XBMC (originally developed for the first Xbox).
The lastest available version is 0.5.0b10 (which still hasn't been rebranded) and is a free download. In addition there is a great new skin for XBMC called Aeon, which works with Plex and frankly looks amazingly slick.