Louis Wu at HBO pointed out that the author of Sybex's Strategy Guide for PC Halo, Doug Radcliffe, posted in the HBO forum that the guide is finished and should be out around the same time as the game. However, more exciting than that are some of the extras that will be included:

• Developer notes from Jaime "Case" Griesemer, Tyson "Ferrex" Green, and Paul Bertone
• Halo Bible Excerpts
• Community Spotlights on HBO, Randy Glass, Miguel "Freewill" Chavez, and Red vs. Blue
• Easter Egg list

All in all, it sounds like it'd be worth buying just for the extras, let alone the strategy guide.