It is a common fact that when people make movies of video games, they rarely stick to the plot. Here's an idea as to what I think the Left 4 Dead movie poster may look like.
The question is, what is the most awesome thing about the picture?
The epic smoker villan in the background?
The Boomer firing a missile launcher?
The fact the Tank is on a bike? (if you aren't humming "Nigga Stole Mah Bike," you are soulless)
You decide.
-=Edit=-
Here's what

thought would happen Plot-Wise:
Troublemaker-Tank ran away with Witch, the love of his life. But her father, the mafia-boss of the Smokin Aces gang does not agree with their love life and sends out his infected followers to capture them. Another Mafia-bosses son, Big Shot Boomer wants to claim Witch for himself.
Tank has no one to turn to but his oldest freind, The Hunter, and an old bike he used when he was still a human. They are up for the biggest chase in the history of infected romances.
Wait....WHUT?