Valve Software officially announced the pre-order bonuses for Left 4 Dead 2. You might already know two of the extras but the third is a surprise.

Pre-ordering the PC or Xbox 360 versions of L4D2 will get you exclusive early access to the demo, which is "currently targeted for October 27th." You'll also nab an exclusive in-game weapon: the baseball bat. If those weren't enough for you, Steam and select retailers will also knock 10% off the game's final price if you reserve a copy now.

L4D2 will be released for both platforms on November 17th. It's not clear when the demo will be released for the general public so it's tough to gauge how valuable the early pre-order access will be. I imagine the pre-order folks will at least get a week to themselves, though.