This may be obvious for some, but for whom it isn't, I want to call it out and describe it as extremely useful: If you ever have to dismantle a complicated audio/video system, take pictures of the cabling before you pull it all apart.
We bought a flat-screen TV and associated media components last year for the lower level, and a Geek Squad guy came out to assemble and test it for us. Now, I'm not a big media guy. I watch movies when I'm on the treadmill, and sometimes TV. I've spent my time learning other things. So when I had to empty out the carpeted areas of the lower level, I took one look at the ratsnest behind the electronics and dove for my digital camera. I took pictures of the cables behind the TV and each of the other components. Yesterday, when it was time to put everything back in place after a two-month hiatus (which is more than long enough to forget everything) I printed out five color copies of the pertinent photos, and had it all reratsnested and working inside of twenty minutes, with no false moves at all.
I recognize that it may be difficult to get a camera behind some systems. If you can, pivot each component out far enough to snap what's plugged into it. If you can't, well, maybe using longer cables would be a good idea.
Having fought with media messes like this on many occasions, I'm guessing that this technique saved me hours I would otherwise have wasted and never have again. Highly recommended.