Experiencing problems with your copy of Halo 3? Don't worry, it's not just you - hundreds of other gamers are experiencing issues as well. Reports from the official Bungie forums are coming in with users complaining about disc read errors, system lockups, and even the dreaded red rings of death.
Right now it is unknown if the majority of these reports are related to the 360 hardware itself - or the Halo 3 game disc. Whatever the case may be, a whole heck of a lot of people are having problems with the game. Hopefully Microsoft and Bungie will release an official statement on the issue soon and clear up the concerns.
"Cannot read Disk" [Bungie.net]