Skill, n. 1) Proficiency, facility, or dexterity that is acquired or developed through training or experience.
Would you not agree that people who have played the game longer tend to be better players? That they possess a certain proficiency, gained through experience, that new players do not? Condescend all you want, but I fail to see how you can separate "experience gained through playing time" from "skill," particularly since that is the very definition of skill itself. Experience with the game WILL improve your reaction time. Reaction time, then, is a skill.
Me, I like CS: Source. Never liked the original CS much, but my roommate and I have been hooked by Source (at least until DOD is released). With all the servers that are out there, it hasn't been to find a good, cheater-free game.