I've been playing Sid Meiers Alpha Centauri for the past 5 days (hadn't played it before, but I'd heard it was good), and I love the game mechanics and the feel of it, but the AI is pretty lousy, and can't keep up with me even on the hardest setting. In my current game, I'm playing on the standard map as the Gaians, on the hardest difficulty setting. One of the AI factions (ironically named the UN Peacekeepers) attacked me at turn 10 or 11, and I forced an unconditional surrender from them by turn 20. It's now 2168 (68 turns have past), and I've wiped out the University faction, which was previously the strongest faction by a large margin, and now my might rating is about three times that of any other faction, which makes for a boring and pointless game.
I could do with some humans to play against, but I've never felt very comfortable with playing against real people, since I worry that I'll let them down or piss them off somehow.