You may find that the 635 has enough juice for you and your m80's. Who knows until you try it out. I think you made a fine decision regarding receivers. And if you need more power, a strong two channel amp will be the way to go as you said. Plus you'll gain the respect of the other m80 freaks. Just a joke. Haha.

Good luck and enjoy.
Michael

*Michael*
AV123 Refugee - X-LS Encore, X-Voce, X-Omnis, Elt-Dpa's
Denon AVR-591
Magnavox NB500MGX BDP