Great update, concise and yet very informative. A quick question about the development process of the game, how do you store the current build to insure it isn't deleted by an error of some sort? Is it kept in different parts, or is there one central beast?
For the build: There's probably one in every dev kit.
As for the source code and multimedia assets, I'd assume Bungie has an SVN version control system set up on a quadruple redundant server cluster that runs a full back up every what, five seconds? That leaves about a .00000001% chance of total data loss (ie. meteor spartan hits the studio and obliterates it and all offsite backup servers in the process - bad luck master chief :/).
[Edited on 05.21.2010 6:08 PM PDT]