I haven't played PC games in a while, so most of the stuff I've played and liked is also pretty old. I really enjoyed Civ3, Starcraft, and Warcraft 2. I have a couple that people haven't mentioned:
If you're looking for more turn based stuff and are open to some pretty old school stuff that's kinda different from the above mentioned stuff, I'd recommend the X-COM series (mainly the first two UFO Defense and Terror from the Deep). You basically run an defense organization that fights aliens trying to take over the world. Most of the game is you directly your team in alien infested areas. It's turn based strategy, but there's other micromanagement things (like keeping track of technology and stuff).
I was also a fan of Imperialism (1 & 2), though I wouldn't be surprised if some people found it boring. It's turn-based world conquering stuff (kind of like Civ), with a larger emphasis on micromanagement... particular on trade/economy. It's kind of like those strategy boards games, like Settlers of Catan.