I would reccomend that you use the processor in the Marantz. The SR7000 sounds very good. I don't know what kind of amplifier you picked up but I would reccomend that you use the surround and middle channel amps in the Marantz and use a nice two channel amp for the fronts. You should be crossing those channels over around 100hz to your sub so the Marantz's amps should easily handle the load. This set up will also eliminate 6 interconnects.
Do I need Pro Logic IIx?
I have a 5.1 system and am upgrading my Marantz SR7000 to separate components. I've already picked up an amplifier and am looking around for a second hand processor. Systems with Pro Logic IIx are newer and second hand units harder to find and more expensive than those with Pro Logic II. From what I've read, Pro Logic II supports five speakers and Pro Logic IIx supports seven speakers. As my speaker set-up is 5.1 and I'm not interested in 7.1, would I be losing anything if I pass on the Pro Logic IIx and go with Pro Logic II?