I very rarely pre-order anything.
When I'm looking at a Triple A title, I usually refer to the publisher, developer, and track records of both parties. From there I base my purchase on whether or not I'd be getting the money's worth out of the product.
I will often pre-order soon after seeing gameplay footage and getting a glimpse at the game engine. Occasionally I'll evaluate multiple times before making a final decision. This may seem very hasty judgement, but I look at the mechanics and gameplay of the game, not the story or the graphics or any other stuff like that. For example, I pre-ordered Black Ops II after reviewing screenshots, seeing gameplay, and just genuinely finding it looked like a fun game to play. I don't have to like a game's story. Hell, if Bubsy 3D actually had good mechanics I would play it.
Like other people, I will also pre-order games that I actually want. If I know well in advance that a game is coming out and it's been a long time coming, forget what other people say I'm getting my hands on that stuff.
I don't favor pre-order bonuses. They give those that had money an unfair advantage, and loyal consumers who waited for a general consensus to be left in the dust. No, go forget yourself. I don't care if you have a stupid 360 noscope super gold plated .50 caliber exclusive sniper rifle with fifteen bayonets because I actually bought the game afterwards to play it not to have an unfair advantage over every other player. Even if you don't pre-order, you don't deserve to be treated like stuff by the community and you CERTAINLY don't deserve to be treated like stuff from the developer, either. I am sick and tired of developers loving over customers and favoring those who shelled out 60 bucks a week earlier than everybody else by giving them exclusive weapons, double XP days, and other non-cosmetic items.
I especially hate when developers take essential game mechanics out of the game and make them pre-order bonuses. Take Metro: Last Light as an example. You're telling me that I have to pre-order to play the game in Ranger mode? The very same Ranger mode that was in the predecessor? That is not only bullstuff, but you are removing a game mechanic THAT WAS IN THE PREVIOUS GAME, MIND YOU in order to milk a couple more bucks out of the consumer.
I'm done. Maybe I'll write a little more later.