I want to install [XBMC][1] on my Raspberry Pi, but I do not know what OS to choose.

There are three:

 - [OpenELEC][2]
 - [Raspbmc][3]
 - [XBian][4]

What is the most efficient of the three? Which allows you to continue to use the Raspberry Pi as a classic Linux system?

  [1]: http://en.wikipedia.org/wiki/XBMC
  [2]: http://wiki.xbmc.org/index.php?title=OpenELEC
  [3]: http://wiki.xbmc.org/index.php?title=Raspbmc
  [4]: http://wiki.xbmc.org/index.php?title=XBian