Here's what you may not have already heard: Activision is giving away the album with the first million North American copies of Guitar Hero: Warriors of Rock. In fact, buying the game will allow you to get the CD a week before it's released elsewhere! Not only that, the album will be available as Guitar Hero DLC at launch.
Cool musical bonuses like this are likely to do much more to pique interest in the latest Guitar Hero game than, say, pig monsters.
Update: Turns out the DLC won't be free! Activision's Dan Amrich changed his announcement post to reflect this corrected information. There's no word on the actual price yet, except that it's not free.