I loves me some real time strategy: Command & Conquer, Dune, Star Wars Galactic BattleGrounds, Age of Empires. Oddly enough, I never really cared for Warcraft or Starcraft though.
There's nothing better than linking up two old ps1's via link cable, placing two tvs back to back and facing off with a good friend in command and conquer or Dune 2000. Me and JJ (my old roomate) used to battle each other for hours. I even got an extra ps1 and copy of Dune just in case such an occasion ever arises again
Dune 2000, I absolutely love the first intro sentence, "On this planet, you will die."