Gametrailers had an exclusive with Valve yesterday. They showed a bit from Crash Course the L4D DLC, and a new campaign from L4D2 that takes place in an amusement park.
There's not much footage, but they do interview Gabe Newell on his plans for TF2, a sequel for Counter-Strike, and HL2: Ep.3. Oh and Portal 2.
As you probably expect, he's very vague with these titles and release dates, which is fine with me.
To quote Shigeru Miyamoto: "A delayed game is eventually good, a bad game is bad forever."
We waited ages for TF2, and its one of the best things to ever happen to the FPS industry. I know it'll be good when it comes out.
/fanboyism