I am looking to make a cost-effective upgrade to my system. I am currently leaning toward a new receiver, but need guidance. I currently have the following: --Sapphire Audio all around with ST1B Towers as my mains --Athena AS-P300 8" sub --Harman/Kardon AVR 130 receiver (45 watts x 5) --Pioneer DV-563A universal DVD player --Monster and Acoustic Research cables What is my best upgrade for under, say, $700? Should I focus on getting more power to my mains? If so, does this mean a new surround receiver, or maybe a stereo amplifier? Should I focus on a better dvd player (I listen to a lot of multichannel music and am pretty happy with the DV-563A). Should I save and get better speakers/sub? Thanks. Your suggestions are appreciated.