Heroes of Might and Magic 3 is my all-time choice
I love HoMM III too, you just reminded me that I gotta hack it from somewhere again (don't have it since my computer was rebooted a few months ago and I lost all the data). HoMM V (despite Mr. Xapy's professional opinion) is also a pretty good one, imho. However VI sucks balls.
Spore is also pretty good, even just the main game (which is the only thing I've got ^)