Have you purchased a Raspberry Pi recently, perhaps the $25 model A? If your goal is to transform the uber-mini dev-board into a small set top box or home theater PC, you might want to check out the latest version of the Raspbmc OS (1.0).
Indeed, the release of 1.0 is a rather important milestone because it marks the first time the development team has been confident enough in a stable build to officially launch the Pi-specific OS for the masses.
Raspbmc can best be described as a port of XBMC designed specifically for the relatively low power Raspberry Pi hardware. The new media Center operating system is ready to be downloaded to your preferred SD card. If you've been running a previous version of the operating system you'll have to uninstall and reinstall the new version.
Raspbmc is based on the XBMC 12 final build and supports DTS 1080p decoding via software. The software also supports a number of video codecs and users of the Raspberry Pi are able to purchase licenses for MPEG-2 and VC-1 hardware decoding off the official Raspberry Pi store. Those two purchases are pretty much required if you want to use the Pi as a media computer.
In addition, the latest version of the OS is capable of detecting unstable power supplies and unsafe shutdowns. It offers language selection and improved support for the Hama remote control. Other updated features include a streamlined approach for handling USB mounting and logs are now written to RAM to decrease SD IO.