Valve have announced that the Left 4 Dead downloadable content will be free:
The recently announced Left 4 Dead Downloadable Content (L4D DLC) will be delivered to Xbox 360 and PC gamers free of charge.
Due for release this spring, the DLC for 2008's best-selling new game property on the PC and Xbox 360, is dubbed the L4D Survival Pack and introduces a new multiplayer game mode entitled, Survival, plus two complete campaigns for Versus Mode (Death Toll, Dead Air). A Critic's Choice Edition of the game will be heading to retail stores this spring, and will include access to all the content introduced in the L4D: Survival Pack.
Nice. It's a little sad that this is good news instead of just par for the course like it used to be back in the old days, but it's still far better than the alternative!