Games : How realistic is Counter-Strike?

I know that Counter-Strike is tweaked to make it more fun at the expense of realism, but how realistic is it (or can it be)?

I have heard that SOCOM is more realistic than CS, so I would be equally interested in that answer for that FPS.

I know that certain aspects are obvious unrealistic, such as allowing players to take a lot of damage before being incapacitated, but assuming that easy modifications for realism had been done, how realistic are these games to real combat?