My livingroom is a little over 200 sq. ft. and I have the m60s, vp150, and qs8s. I think they sound excellent, but you want to make sure you sit at least 10' or so back from the m60s and that you can separate them by a similar amount in order to get a well developed sound stage from them. They are more than adaquate to fill a room that size with clean, loud sound. As for the reciever, I have a similar quality Kenwood VR-507 with 100 watts per channel. It does the job just fine, and I can crank it up to pretty painfully loud levels without noticing any clipping. You will however, almost definately, find yourself wondering a few months after listening to everything what it would sound like with a nice HK or Denon powering it. I have been fighting off that itch for a little while now myself, and will probably succumb to it before the year's end. But, I suspect your sony would run my set up just fine. As for subs, people here will probably point you to Hsu and SVS.
