I just bought a HDTV and a THX receiver (Pioneer), and now need to upgrade my speakers to complete my 5.1 system. I will need a good movie system obviously, but to be honest I primarily listen to music... and the den is about 15' X 15'. I was looking at a 533VAC for center, 533 Towers for the L/R channels and using my Infinity bookshelf speakers for rear. Two concerns that hopefully you guys and gals can allay: 1. Do I really need a sub? I think the towers will give me enough base for a relatively small room, and it's a condo so I also don't relaly want to ostracize myself with big BOOMS during Sci Fi movies... Will the towers be ok for me? 2. Will my current Infinity bookshelf speakers serve adequately as rear channels? They are pretty good sounding speakers, perfect condition, but they are about 8 years old... Thanks in advance, can't wait to decide on the set up so that I can get my early Christmas present to myself!