Here just some upaid advertising for a nice armhf-based XBMC distro, I discovered some time ago. If you just want to use your RPI for watching movies and TV-shows, this is definitely for you. It auto-starts XBMC, mounts USB-drives and lets you connect to NFS and SMB as well. They only thing you might want to do is keep your XMBC-user folder on a different drive, so you can easily switch versions and always have a backup.

Link: http://xbian.org/