xhonzi said:

I know C3PX would be up for L4D2, but I only have the first game so far. Also it seems that 4 players is really the only way to really play L4D... it's not quite as scalabe as Halo 3. But maybe I m wrong about that.

We still have L4D1 too. Can't get rid of that, its a classic (and they're still making episodes for it)!

Its not required that you have 4 players, most of the time we'll just have 3 and end up killing the extra AI because he usually gets in the way. If you're going for random achievements, some of them are pretty much impossible without having 4, but for playing around 3 isn't bad. Besides, I'm a package deal, my wife plays with me.