The title says it all, and the preorder bonus comes with a special weapon and a free future DLC!
As for a cool little research project, there are some good articles out there talking about the problems arising from buying and selling used games and the effect it's having on the gaming market. Many companies now offer these preorder bonuses just in order to combat the distribution of games this way, and EA is even taking steps to restricting gameplay to those who buy them used.

Oh yes, finally steam introduces a new Zombie game (unfortunately not Dead Island, YET, soon should be available for preorders though.)
The game Trapped Dead is a RTS with the traditional zombe as its main enemy. Sounds strange and all, but it should be great, and if not I'll write a review telling you how much it sucks. Buy it while it's hot and 20% off for only $8!

This AMAZING game is on sale for only $3 on the steam store right now, go check it out, go youtube it and watch Totalhalibut play it, feel the neccassary urge to buy it, and join us.
Hit me up if you buy it and want to play!

If you haven't already noticed, and I know you have, today steam's summer camp sale is somewhat zombie themed.
If you miraculously don't own left4dead by now, go pick it up for $5.

A great hidden gem of an indie game that you definitely need to try out is Atom Zombie Smasher, an over-head stratagy game that has you trying to rescue humans in a city before the zombies can convert all of them. Send in a helicopter to pick them up and use an arsenal of mercenaries to take out the zombies, ranging from snipers, infantry, land mines, zed bait, and more.
And for only $3!