XBMCbuntu
XBMCbuntu is a free Ubuntu-based Linux distribution with XBMC for Linux already installed and pre-configured, providing a complete packaged media center software suite for all IA-32/x86-based personal computers. XBMCbuntu uses XBMC Media Center for all media playback and is primarily designed for bare-metal installations to achieve instant on type boot to achieve a set-top box experience on a HTPC. It replaces XBMC Live, which was formerly the official LiveCD distribution.
XBMCbuntu 11.0 (Eden) is based on Lubuntu, this is because Lubuntu is "lighter, less resource hungry and more energy-efficient" than the standard Ubuntu distribution).The Microsoft MCE Remote and IR-receiver dongle for Windows Media Center works with XBMCbuntu directly out of the box, which mean that Windows Media Center users with these can try out the XBMCbuntu without requiring any additional hardware.
Following the principles of Myth TV distributions and GeeXboX, XBMCbuntu is designed to simplify a permanent installation of XBMC Media Center onto a computer to be used as a dedicated home theater PC in the living-room, as such the user can directly install XBMC Media Center from the bootable CD to either a USB flash drive or to an internal hard disk drive as it comes with a complete instant on (Linux-based) embedded operating system. When installed onto a USB flash drive or internal hard disk drive, XBMCbuntu has the ability to save settings and make updates to XBMC Media Center and the operating-system back onto the USB flash drive or hard disk drive that it is installed onto.
Read more about this topic: XBMC, Official Versions