Havent seen about 25 of those films, yet (and I dont plan to see them all), but I think the AFI list is more or less a representation of similar "consensus" lists. As an itroduction to American cinema it's fine indeed, but a list compiled by experts should not contain so much usual suspects. There couould have been some more surprises and unknown films. 
As a comparison I recommend Jonathan Rosenbaums alternative Top 100 (I don't have the link right now, but it shouldn't be too hard to find on the internet - EDIT: here's the link: Alternative 100). 

My own list would probably be a mix of the two, and some rather unknown or underappreciated additions. 

What if everyone makes their alternate Top 100 US Movie List? 
Shouldn't be too hard, and would sure fuel some discussions, as well as revealing some unknown treasures.