Here's a question I've wondered about on occasion: would an array on the dark side of the moon be shielded from terrestrial interference or would the 'ambience' still be so great that it wouldn't make much difference? In other words, if SETI were set up on the moon, could it search the entire spectrum, or at least much more of it?
Would be excellent! :-) We would still have the pesky galactic halo noise below about 1GHz though.