We recently moved into a new place. The previous owner had the living room professionally wired for surround sound (wiring inside the walls). So we have these vacancies with dangling wires where speakers used to hang on the wall. I'm not a tech junkie (don't watch much tv beyong the news), but I figure we may as well take advantage of the pre-wired set-up and get surround sound speakers. So, lacking all knowledge of these systems, how is this done? My sense is I need a receiver which will take input from my tv and feed out to the speakers, yes? Any recommendations on brands/systems? Number of speakers? In general, what do I need to know before I buy? Thanks.