Games with powerful AI

[Havoc]

Which pc games with challenging AI do you recommend?

Unfortunately the majority have a poor, dumb or even retarded engine. In my opinion only a few have a decent AI, some of them:

-Squad Battles
-First World War Campaigns
-Europa Universalis IV
-FEAR
-Pike & Shot
-Sengoku Jidai
-Command Ops 2
-DC3: Barbarrosa
-Heroes III of might and magic+HOTA mod
-Field of Glory II

Any suggestions?

Problem with even the best AI's is they will follow patterns that once you know, you can't forget.  I prefer games against people, but I have had a good challenge from (just to name a few):

-Total War: Empire (though the AI does have a tendency to launch cavalry across the field unsupported)
-Total War: Napoleon
-Strategic Command WWII: War in Europe (if you can refrain from taking advantage of the AI's launching waves of U.S. AV's and transports straight across the Atlantic to England un-escorted!)
-Pike & Shot
-Galactic Civilizations II Ultimate (got to keep your eye on what AI players are building into their ships or your fleets will be trashed)