These are my personal favourites, but any other suggestions welcome.
I fixed it for you. There is no 3. what you played was the cake from portal.Out of the Commander and Conquer series I've fallen in love with Tiberian Sun and Red Alert (all 3).
Age of Empires, 1 and 2 of those as well :drool:
Haven't tried Starcraft, but I guess I should.
Total Annihilation: Kingdoms is ozzim!
I enjoyed Warcraft 3 for the most part, but mostly for the lore.
Another game I've enjoyed was Pharaoh, it's a strategy game, dunno if you guys think it is one, as it's mostly (if not all) single player. No real contact with other players/computers in game.
I can't decide on one game