Reports are coming in (both across the internet and directly to TheFeed) that some of the Halo 3 Collectors Discs are coming pre-scratched due to packaging issues. Most seem to affect the "extras" disc, and all reports thus far have indicated that the scratches were not deep enough to make the discs unplayable. The photo below is from NeoGAF, where you can find a bit more information.
The regular edition seems to unaffected (this uses standard Xbox game packaging).
TheFeed suggests that you check your discs in the store, so that if there's a problem, you can handle it quickly and easily. Don't panic, M'Soft made a bajillion of these discs so it shouldn't be a problem to swap them out if there are indeed widespread issues.
The game - by the way - is absolutely awesome, and playing the co-op campaign on legendary over Xbox Live with three of your closest friends is EPIC.
TheFeed will bring you more thoughts and impressions on Halo 3 later today (or tomorrow morning if we can't force ourselves to stop playing it, which is highly likely), and of course Kevin, Olivia, Adam, Morgan and the rest of the gang will bring you 5 and a half hours of LIVE countdown coverage tomorrow starting with AOTS at 7pm ET.