It seems there is much more interest in separates than I thought.
A really good unit like that Marantz 7705 can really be the basis of a good AV system.
I really like mine, and still have two of the previous generation in regular use. The sound is superb, and the unit is now really well debugged with the software updates.
If possible rack mount it. Also I would counsel against power amps with single power supplies powering a multiplicity of power amps. I'm not sure that really harnesses all the benefits. If I did not have a large collection of Quad amps, then I think I would use 2 channel pro amps rack mounted. This makes for increased reliability and only have to replace a single 2 channel amp rather than all your amps.
Now if you do get a collection of high powered 2 channel amps, the turn on in draw current is high. For an 11.2 channel system this will require 2 circuits of 15 amps at least. You should also install magnetic shunt breakers on those circuits, to handle the in draw turn on current.
If the amps do not have front mounted switches, or if you want the amps out of site, I recommend a 24 volt system of relays, and a switch unit in an accessible position.
24/27 volt transformers and relays are easily obtained and are not expensive. They are widely used in HVAC systems. My mechanical/HVAC room is peppered with them.
This picture shows the type of transformers and relays I'm talking about.
You can see the lighted switches are arranged to start the left and right main amps, center amps, surround and ceiling amps, and the rear back amps.
This allows you to just switch on the amps you want to use.
UPS to power the pre/pro and peripheral units and TV, but not the power amps.
I really think this makes for a robust and stable installation.
I think these systems are getting much more stable. I can't imagine we are going to require anymore channels in domestic installations than we have now.
In terms of screen resolutions I think we have well and truly reached the limit of human biology. What I am getting at is that pending some totally revolutionary technology obsolescence will become progressively less of an issue. So I think the gains from putting in robust reliable systems will move to the forefront.
If active speakers start to really take hold, which I think they will, then a unit like this makes the transition easy, given the XLR balanced outputs.
I actually do not use the features built into these type of units. Once set up I just use the unit to select inputs and sound modes, and then control the volume. I only use Audyssey to balance the speakers, and none of its Eq functions. Everything else is from the peripherals.
So I think the 7705 can be a major part of a reliable and robust system with the expectation of longevity in a professionally planned and executed installation. In my experience going about it with this mind set actually over time ends up being the most economical on the budget.