Something else came to mind. It may not apply to your situation, because it sounds like you may be fishing speaker cables through existing walls and existing electric lines.
But if you are not, i.e. if you are building something new, then make sure that your electrician puts in all his lines before you run your speaker wires. I've heard secondhand stories of people who've laid in their speaker wire and then had electricians come in and run their electric lines right along the speaker wire. That's great for the electrician - saves him the work of drilling new holes in the 2x4s, etc. Sucks for the homeowner, though!
