I've already Left 4 Dead 2, but I didn't enjoy it too much, maybe because I've played it with random people and without communication.
I'm thinking about getting Counter Strike: Global Offensive, 'cause it's cheap and from what I heard it's one of the best teamwork-based fps.
Tomorrow, before the daily sales expire (should be 18:00 UK time), I'll make my choice.
Edit: Oh, no, the offer is expring in 2 hours... Ok, I'm buying it!
First purchase of the Sales!
I'll make a list in the first post with every our purchases!