I have an Apple TV, attached with an HDMI cable to my TV. The TV is attached to my amp with phono cable. I haven't bothered to get an optical cable long enough to go all the way from the Apple TV to the AVR yet! The Apple TV is connected via Ethernet into a switch, which can connect to my file server which exports NFS shares. I previously had problems with NFS and nitoTV, and then AppleTVFiles, but upon moving to Boxee, these issues have completely disappeared.
The Apple TV itself has firmware v2.3, with Launcher, Boxee, and XBMC on it (although I've never tried XBMC).
Does that sort of explain it?