I've never preordered, and given the current trends in the industry, I never will. I've learnt my lesson with Assassin's Creed 2 and worked out a system:
If I find out that a game will have DLC or preorder-exclusive content, I wait a year for the game of the year edition. This usually includes all the DLC and "exclusive" content for only about $40. Sure, I have to wait a year, but a year-old game is just as good as a recent one.
I've used this system to get Arkham City, Borderlands and Red Dead Redemption with all the DLC for a very low price. It's worth the wait, as far as I'm concerned. I'm doing it with Borderlands 2 and Assassin's Creed 3 as well.
EDIT: Oh, wow. I just realised that you said the same thing as me in the OP.