I'm using a Sony 5200 to drive 7 B+W M-1 speakers and two PV1 subwoofers. I find that, when watching a film, the back speakers don't always work. My understanding is that it depends on the audio options on the DVD. That is, is it mastered in 6.1 or 5.1 audio etc.
As for the subwoofer, I have just daisy-chained them together via the RCA line-in/line-out.
I'm sure it isn't the best way to configure the system, but it works. I tried Master and Commander on it the other day. The opening canon fight scenes utilised all the speakers and the result was terrific. The sensation of wood splintering around you from the canon impact was great.
I find the extra subwoofer balances things out nicely and provides additional depth. Placement is important. One on each side of the front speakers seemed to work nicely for me.