I agree with Bridgman on applying the cost difference between the M60 and the M80 toward the EP500. It'll really make all the difference.
I remember when I bought my M60s I was worried that once I received them I would be wishing I'd purchased the M80s instead. This never happened. The outside of the M60 box says High Performance Loudspeaker System, and they aren't kidding. My room size is very similar to yours, and the M60s are more than adequate for it...way more than adequate at all volume levels. Without hearing the M22s, I feel confident the M60s were the right decision. If I had to do anything differently, I would buy the VP150 over the VP100, but still, I'm very happy with the VP100 and it fits well within the limited space I have for it. My limited space is also the reason why I went with the SVS SB12-Plus sub. It's proven itself to be an excellent performer in my system without taking over the entire room.
Once I get my downstairs finished next summer, being a much larger room no doubt my choice will be the M80s, QS8s, VP150 or M22s for a center solution, and the jury is still out on the sub solution.
