I'm usually one who waits for reviews too. There were only two games last year that I preordered, Borderlands 2 and Dishonored. Just the other day I pre-ordered Grand Theft Auto V from Gamestop. I tend to pre-order games that I'm really looking forward to, franchises and developers and studios who I know are going to do a great job (Bethesda, Rock Star, etc.).
Mostly I just look at game magazines when I'm in the can and see what catches my eye. If there's an interesting/decent preview, I'll keep an eye on it. If it gets good reviews, I'll buy it, usually after it's already out.