Yea metal studs are a pain. Best thing to use is a hole saw. I usually put my drill in reverse and the hole saw works sweet. If you do it in forward sometimes it (the teeth on the hole saw) catches and if your not superman it can hurt. lol
A Sawsall works good to.
Hiding wires takes some planning. You really need to know where your going to be setting things up. Are you going to have 2 or 3 different locations? If you are then try and consider your needs. Ethernet in the walls is a must have unless you're going wireless. USB ports arn't needed really and the distance that signal can travel is limited anyway. Also running speaker wires in the walls is sweet. But, you have to know where you want them. Because changing that is hard once you sheetrock.
I used keystone inserts. you can put any array of inserts in 1 box that you want. But fro the surround sound i had to use a 2 gang box.
http://www.mycablemart.com/store/car...duct_list&c=89