First off, I can't stand the style of the official site. I'm a web dinosaur and I like websites with a more classic feel. Flash is an abomination and should be banished from the planet.
I also don't like the whole empty link thing - links that point to 'coming soon' pages. It's very amateur. It's what I'd expect out of novice web developers (I'm a web app programmer and I've been in the industry for 10 years or so now).
I guess some info is better than no info - but sites like this one and many others have more info than the official site - so I don't see why they put up a weak effort that just looks unprofessional.
I play a lot of games. Many great games have poor websites. It's not like having a great website is a prereq for a great game. But if you're gonna put up an official site and give the impression of providing information then DO IT. Don't tease. Don't publish a website that looks like a high school project. And do create a website viewable by all browsers on all types of machines instead of a steaming pile of "art."
I expect that most people who visit this site and/or post in this thread will be buying Civ IV...period. If you weren't a Civ junkie and saw that site today, and found out the game was coming out in a week - what might you think of the quality of that game?
Fortunately there are sites like this one that DO have good information and a tolerable layout and style.