Yesterday reports surfaced of what appeared to be a scratched disc problem with Halo 3 Limited Editions. It seemed that the plastic used to hold discs in place wasn't designed too well. In a small note on the official Xbox site, Microsoft today admitted the issue, and offered free replacement.
NOTE: This program covers the Halo 3 Limited Edition Game Disc and Essentials Disc at no charge through 12/31/07.
If you really want it fast, go back to the retailer ... but there's
always the chance those will be scratched (during shipping to the store)
as well ...