For those that have pre-ordered or intend to pick up their Limited Edition of Halo 3 today, a word of advice: open the case and inspect the game disc in the store before you leave. I had heard about problems with the Limited Edition having discs come loose during shipment and rolling around in the case, which can end up scratching the game disc pretty badly.
When I picked up my LE at a local GameStop, I opened mine right away and turned right around. I walked back to the counter, told them what I saw and they knew immediately what I was talking about, and apparently Microsoft knows about the problem. The clerk I dealt with just cut open a regular Halo 3 edition and swapped the game disc with me, so that’s probably your best option if you can swing it.
Again, be sure to check your game before you leave the store, because otherwise, if the game is unplayable, you’ll have to return to the store or possibly even have to send the game back to Microsoft, which might take days.