I only pre-order a game if its something I know I definitely want to get, such as a sequel to a well established series or something that will be limited in stock upon release (hello Dragon Quest games or third party Wii titles). Many times however, I won't pre-order a game now adays because places like GameStop will open your game and mess with it before giving it to you. Or they'll 'pre-order' it for you weeks or even months ahead of time, then make you wait 1-3 days later than the scheduled release date due to 'shipping days' for the game to arrive.
In short, I'm just disappointed in places like GameStop and try to buy my games anywhere else I can first. And only buy major games like Mario there where I know they'll have 500 copies on day 1 (which don't even need a pre-order).
Six upcoming games you should look into:
