What game uses voice-chat the most?

Sorry if this isn't ordinary SW material, but I'm just wondering, is there a game that you go into and EVERYONE is using voice-chat? And what game is that?

CS:S

CSS

there are games on the PC, such as Arma2 where its pretty much required.

Uh do you mean using voice chat for teamwork, or just talking in general. A lot of people in COD talk but not about anything useful. I find many people in L4D2 talk