With L4D being as popular as it already is I'm sure it'll be on top. it wont' stay long though as after playing the demo, it's only marginally better than the first, so it's popularity will be directly related to how often it's updated.
Also you guys seem to be confused. That screenshot I posted was for the wegame clan members ONLY. The screenshot below shows Xfire's top games for the day (minutes played are the minutes so far today from midnight's reset).
This is probably the closes a game has come to knocking wow off the top for the past 4 years. Yes, WoW has been on top of Xfir'es played games for 4 years. Also before any of you point out I understand not everyone uses Xfire, but enough people use Xfire for you to get a grasp of what's popular in the gaming world.
For example, when trying a multiplayer game, you can check the games list and see it's played time to see about how much it's being played every day. almost 100% of the time, if there's little to no play time on Xfire you can be 100% sure that when you log onto that game you won't be able to find people to play with, or it'll be very very few games.
14 million people is a good enough representation to see what's going on in the gaming world.

