...how about moving into the late 90's and dispensing with all the xhost + nonsense and enter
ssh -X firstname.lastname@example.org
in your xterm window (with the obvious substitutions). No need to set the display on the host machine, no need to allow *everyone* on the host machine to play tricks (or worse) with your display, just nice clean encrypted fun. That is, just start using X apps on the remote machine after logging in with this command. If you're on a slow link then add in compression by using a -C flag as well. Muuuuch nicer.
Paul (err, "anonymous")