"I'd play it safe and go with M60s and the most monstrous sub SVS makes."

Definitely. The M80s seem to be geared for high end stereo systems for listening to music predominantly, if not exclusively. Although it can handle any bass you'd encounter listening to music, you'd still need a subwoofer for HT. So get a ridiculously big one. The M60s paired with that will be second to none. And make sure you have enough in the budget for a pair of QS8s.