Just picked up L4D2 for £12 by getting the four pack with some German chaps. Their version is censored and costs the equivalent of £41 over Steam, so they Paypalled me cash and I gifted them all cheap, proper copies.

With this in mind, I'll post the IPs of my usual haunt, the Hampshire Heavies. Usually a right old mix of players in there, but always an excellent game:

217.146.85.240:27015
217.146.85.241:27015

Mahapsably see you in there.

I have to back McClane up here, the unlockable weapons are not superior, they're merely alternatives. I regularly play TF2 and maybe I'm just on the right servers, but I've not witnessed any change in playing from others due to the achievements (except for the first few days after a class update obv...