http://www.shacknews.com/laryn.x?story=55618

From link:

Pre-sales of Valve's zombie shooter Left 4 Dead (PC, 360) are outperforming those of the company's hit game collection The Orange Box by nearly twofold, according to the developer.

"Pre-orders are now running 95% over those of The Orange Box, and we're getting set to launch the pre-release demo and television campaign to further fuel this momentum," said Valve marketing VP Doug Lombardi in an official release.

Valve announced earlier today that customers who pre-order Left 4 Dead will receive access to the game's demo a full week prior to the November 11 release date.

Lombardi also announced the launch of a new Left 4 Dead contest, inviting fans to capture creative poses in front of Left 4 Dead outdoor advertisements. The entries will be judged by Valve's Gabe Newell, with the top 25 receiving free copies of Left 4 Dead. The grand prize winner will bag a new gaming PC assembled by AMD.

i saw a huge L4D billboard ad earlier...

almost ran over a car...

I knew Valve was putting out billboards here and there, but I've seriously seen nearly a dozen in Chicago already.

Can't wait to see how much TV advertising they do.

Of course this game is outdoing Orange Box. 2/5 of Orange box was old, that cuts out people who didn't want to buy some parts over, plus this is the first time they've really released a brand new stand alone game on 360 on day 1 and they've done an admiral job of hyping this game. They're showing Epic how you release a PC/360 game properly as opposed to the disaster that Unreal Tournament 3 became at launch.

This seems like an obvious 1.3 million+ seller on 360. No idea how trends go for a game like this on PC but I'm sure another 2 million there easily. I should have this game before the end of the year.

Considering Orange Box sold at least 2 million on PC, I'd wager just under 3 million easy for PC. 

Steam brings in constant sales with no worries about restocking shelves, and there will be big content updates like with TF2...and they will bring those updates to 360 more often as well.