Hiya Pete, welcome.
Another vote here for M60's with a decent sub (like the EP350, Hsu VTF-3, SVS PB12-ISD, etc.). I do not know how much you planned to spend on a HK-7300 (because such notions are so far beyond my reach), but if you are squeezed budgetarily, I'm sure that the remanufactured AVR-630 ($598) or AVR-7200 ($898) available directly from
HK would also be excellent choices.
In no case would I consider foregoing either floorstanders or a good sub in a room that large.
If you're coming from Bose as a reference point, you're going to be absolutely blown away by just about any HK/Axiom combination.
