What's your favorite PC exclusive?

[okr]

Modern PC games: Civilization 5 followed by Anno 1404 (although both were released already years ago).

Back in the day: almost all LucasArts adventure games, Civilization 1 and 2, Dungeon Keeper, Dune 2, Outcast, Age of Empires 2, Warcraft 3, The Settlers 2, Baldur's Gate 1 and 2 and many more.

Overall: probably Civilization 2.