Questions and a comment:
Have you heard ANY of the speakers you are considering?
Are we talking about US$ or CDN$?
Fundamentally, I very strongly agree with Mike (mdrew)'s approach. However, there are a couple things that could save you the money to get under budget. In my order of preference:
Start out with 5.1 or 6.1 instead of going straight to 7.1 and buy only 2-3 QS8's instead of 4. There is very darn little discrete 7.1 content out there.
You need the room for a floorstanding vertical center speaker. If that doesn't "work", go for the VP150 and be happy/confident.
Consider the Hsu VTF-3, the Outlaw LM-1, SVS-PB12-NSD/V, et al. It might be all the sub you ever need. Call the manufacturers and talk to them about your room size, listening habits, etc. But - I want to stress this - if I had your budget, I would buy the EP500 and not look back.
Obviously, I'm an Axiom owner and if you stay within their lineup, I would not deviate from the M60 main and QS8 surrounds. Big thumbs up on the Factory Outlet if you can stand the wait - mine are basically flawless.
I have heard the Rocket 750 and 850, but not the 760. I found them to be very different from each other, and I did not care for the 750 compared to the M60's. They are quite different.
If you can listen to any of these speakers somewhere, I strongly urge you to do so.
