To those who use DTS-ES or DD-EX, how much does the added center rear speaker improve? Will it add to an average system or do you need a Super-Duper set up (i.e. $10,000+) to notice a difference? I understand that the more speakers you have, the more of a surround you'll get and I wouldn't NOT get it if I had a choice, but is it worth it enough to go and replace my receiver right away, or is it more of a 'luxury' item and I need not worry until I'm ready to replace my components? Also, is there a specific scene in a DVD that uses this technology to the point that there's a big difference between the 5.1 and 6.1?