It's amazing this game has maintained such a loyal following despite the fact that other games have come out that look better and run on better technology. It has to be the realism of the game in my opinion. I can't think of any other fps that is as true to life as cs is.
By the way, who here is looking forward to Counter-Strike: Condition Zero? I've seen some screen shots and it looks sweet. There is a great preview on cs-nation.
preview
The best thing about this game is that there are several people who play it on my campus. We even have three dedicated servers on the campus's network which translates to nearly lag-free gaming bliss!
