Those who pre-purchase through Steam get two exclusive Wolfenstein-themed items for TF2; the heavy armour "Die Regime-Panzerung" and soldier hat "Der Maschinensoldaten-Helm." There are now apprximately 6 billion hats available for Valve's team-based shooter.
Wolfenstein: The New Order drops on May 20. All pre-orders also get access to the beta for the next Doom game, whether they're over Steam or not. You can read our first impression of The New Order .