I now own Left 4 Dead. It appears quite good, but I would like to play with people who I can rely more upon not to, for example, hare off into the distance alerting every zombie in the world to our location and then die and demand everyone heal him.
Left 4 Dead is a co-operative zombie-based shooty game. Very co-operative. You need to stick together or you will die. You need to not be a moron, or you will die. You need to both support and rely on your team mates. Or you will die.
(And then you will play as the zombies, and the humans will die instead).
If you would like to play with me at this game over christmas – or Team Fortress 2, or many others – you should friend me on Steam: