CS is best played at 800x600 or 640x480 I can't remember which, because it was designed to be played at that resolution. Using a bigger or lower resolution screws with the aiming. You have to search some pro cs site to find out more, this is just what I have heard.
I heard about this too - I don't think it was "designed" for them so to speak, but the hardcore CS freaks who play in tournaments swear by it. That is the primary reason they have been so reluctant to embrace LCD's (even in 2006); they feel that unless they are playing at one of those low resolutions on a CRT monitor they are losing a competitive advantage.
I remember about a year back there was an announcement by one of the major tourney hosts that they were switching to LCD's all across the board and based on the forum thread response you would have thought these guys were being forced to play blindfolded or something... :wink: