XBMC is an excellent free open source media center that's been labeled as a "High Definition Hub" for all kinds of media.
Because it's open source, XBMC has been modified by some users to create Plex although XBMC is the original base on which Plex is built. Which one you prefer will depend on what you want in a media center but XBMC is a pretty good contender being easy to use, slick, and supported by a large community of enthusiastic users.
XBMC has a highly “skinnable” interface meaning that it can look radically different based on which skin is used. Confluence is used by default, so this is what will greet you upon install but you may wish to change it to something else using some of the free skins here. Some of them are absolutely stunning.
XBMC functions very well as a standard media player although it's far better if you use as a complete home hub for your entertainment needs. XBMC supports a huge range of remote controls and keyboard shortcuts, and it feels like a real entertainment center. XBMC can be used as a standalone player or to stream videos over a network. You can stream your multimedia from anywhere in the house or directly from the internet using practically any protocol available. For example, XBMC can play CDs and DVDs directly from the disk or image file, most popular video formats on your hard drive, and even files inside ZIP and RAR archives.
If you want it to detect what you have, XBMC will scan all of your media and automatically create a personalized library complete with box covers, descriptions, and fanart. Finally, there are playlist and slideshow functions, a weather forecast feature and many audio visualizations.
XBMC is a fantastic media center although if you don't want to go to the hard work of customizing it, Plex may offer you a better alternative.
