If price is no object, then OhioKyle's solution is obviously the cleanest.
However, I will say that, for my money, a hole in the wall with a one gang wall plate is all I needed. two less connections to worry about - not to mention the possibilty that wires get lose or lost behind the wall. Also, if an upgrade is need, not only do you need new wires, but you'll need a new gang-plate.
It's all too much for absolutely no gain, in my book - especailly when the whole mess will be covered by the plasma and the AV cabinet.
Actaully the price isn't all that high for any of the solutions at the 3 sites. And it is how I'm doing the AV rack that'll make a difference. I'm not going with a traditional rack. Instead I've designed a "floating" concept to mimic the display. Everything will appear to float in mid-air on a black wall so the wires/cables cannot be visible. Also this is an outer wall - insulated and vapor barriered. Any holes will have to be filled with expanding foam to seal them! If, down the road, I want to change it the drywall will have to removed anyways!
But you are right I still could use "gangways" even for my solution, it's just personal perference!