I am looking for a very good pair of surround speakers to match the following system: Onkyo 797 receiver, Panny RP91 DVD, Pioneer Elite 520HD RPTV. I have Polk Audio Monitor M5 Series front speakers and a matching Polk Audio center speaker. I also have a subwoofer. The speakers will be wall mounted on the side of the listening area, pretty much in a corner. While I don't want to break the bank, I would like to get a good set? Are dipolar speakers the right choice? Which ones? Thanks.