Here are the ten top selling titles on Steam for the week as reported by Valve:
1.Assassin's Creed IV: Black Flag
2.Call of Duty: Ghosts
3.XCOM: Enemy Within
4.PAYDAY 2
5.X Rebirth
6.Arma III Collection
7.Football Manager 2014
8.Arma II Combined Operations
9.State of Decay
10.RAGE