Oh, yes, Cris mentioned a good one. Wiring minimizing. My speaker cable for instance contains 4 conductors, so the ones that go to the rears can each do two sets of drivers. Shorter cables can be bought to replace excessively long ones. I've really started to make use of 1.5 foot USB cables instead of the usual 6 foot ones that come with everything. Shorter HDMI cables, etc. too.

Tony, if you built out that surround you could even hide the equipment itself. I know it wouldn't work in front of a TV. I put all my gear inside the cabinet behind closed doors even though I'm still trying to keep the wiring neat.