XBMC is clearly the best option around for a media center. The interface is fantastic, there are multiple views and skins, the setup is easy, the add-ons work well, the filters and search options are great, and they keep improving it. The 360 media player is a joke compared to it. You can stream over nfs, samba, or even uPnP. Now that it can run on Raspberry Pi - people will be able to get the best setup for less than $35.