The UT and Q3A days were a classic time for competitive PC gaming! I loved them both but Q3 (specifically duelling) had an extra touch of class in my eyes.
TF2 is a weird one. I think it's undoubtedly a 10/10 game, but all the evolution since release has made the experience a bit "bloated", to use a normal software term. It's almost as if the game has had too much support for its own good.