To me CS is still a classic FPS. All the other FPSs mentioned only appeal to me on a casual gamer basis.
ie, "Oh wow i get to play the landing at normandy in MOH:AA".
or
Castle Wolfenstein - "Yeah kill Nazis"
Ultimately these FPS games appeal to me only because they promise something new, and demonstrate an odd quirk that makes the game different. But with RTCW, everything cool about the game was exhausted after the first two levels. From then on it got repetitive and boring.
CS on the other hand didn't exactly innovate or come up with anything revolutionary. Although I too haven't played it in ages, I still feel it belongs on the "Classics" list of games. Along with any title by blizzard (except blackthorne) and Tekken Tag