6. Be incredibly persistent
The best way to get a system on launch day is to do "all of the above." Camp out overnight, even if you have a pre-order. (Camp at the store where you have pre-order, though!) If camping doesn't work for you, check out the tracking sites and forums and keep searching until you find some good leads on a system. Be willing to drive to a remote suburban area and go to Wal-Mart, K-Mart, or any other Mart you can find. Most gamers will tell you that, if you take the day off of work or juggle your school schedule somehow, you can find a system on launch day if you really want one.
Now, paying for it is, obviously, an altogether different challenge. You're on your own for that one.