I agree wholeheartedly with Smash and Ren.
I own both Civ II & III, and have just been disappointed by 3. I had an immense anticipation of Civ III in the moths before it came out and bought it almost immediately, but found it much less playable and less interesting when it did work. I recall a Sid interview from a year or so before Civ III's release where someone asked him point-blank if Civ III was going to be all about snappy graphics or gameplay, and he answered something to the effect that the snappy graphics would be kept to a minimum. That obviously isn't what happened in the final product.
I downloaded all the Civ III patches, tried several times to get into a game, but each time found myself forcing myself to stick around, to keep trudging on for posterity. I lost interest. I finally, a year later, gave up just last week and decided to make room for other stuff on my hard drive by unloading Civ III.
One thing I'd like to add to the excellent points Smash & Ren made about Civ III's play shortcomings is that expansion is so limited in Civ III. I loved being able to build or conquer so many cities in Civ II, and the list of my cities was a badge of honor. I am unable to repeat those long lists in Civ III.
That all said, Civ III does bring many innovations that I liked to the genre and would hope to see them in a next generation game; the border concept and the colored map that came with it, the expanded diplomatic abilities (though they're still weak), the greater customization abilities, etc.
Ho hum - I guess I'll just stick to my beloved Civ II for the while.