Dan, welcome. You do have a rather wide mix of speakers from different manufacturers. I think that I pretty much followed what you have in mind and my first thought is that the M60s would be fine for the size of your family room. Next, as to what receiver, I have to suggest that "test drives" of different receivers at audio dealers are useless. If there was any significant difference heard between the fine units that you've mentioned the strong suspicion would have to be that all factors(especially equal volume)weren't held constant. My suggestion for the M60s(or M80s)would be the new Yamaha 2700 if it fits your budget.
