In determining the room size for selecting a system, should adjacent rooms with cased openings be considered. For example, my great room (where the system will go) is about 20*18 with 9' ceilings. It has a fairly sizable cased opening to the dining room (14*12) and smaller cased openings to the foyer (8*10) and kitchen (14*25). Since sound will leak into these adjacent rooms, should I consider their square footage in determining the right system?

I just ran the system configurator and, based on a 250-500 sq ft area, it recommended the Epic 60. I am wondering if I should have used a larger square footage.

better go with the epic 80 system to be sure.

;-)

Your house seems just like ours -- the "fashionable" open-floor plan, huh? Given the total connected floor area of nearly 1000 sq. ft., I would at least go with the combo of the M60s/VP150/QS8s plus a Hsu or SVS sub. If the budget allows and/or if you like to listen fairly loud (say, over 90dB average in louder passages), upgrading the fronts to the M80s wouldn't hurt.

I'm a little bit concerned about the 4 ohm M-80 speakers. I recently purchased a NAD T752. Does anyone know if this receiver is up to driving the M-80s?

Yes it will. No worries!