I just can't be as down on Dulles as most of you. Yes, it has its annoyances, but many other airports do as well. Even the highly regarded National has a number of design flaws. Certainly I have not yet been to an airport that really is effectively designed for post-911 security. I do agree that Terminal C is pretty lame, but much of Laguardia and JFK are as well.
Don't give me the line - it isn't about comparisons - of course, it is. It is only because the IAD design isn't the best out there, that causes you to complain. If every other airport in the world was like Brazzaville's Maya Maya International (randomly selected horrible airport) , you would think Dulles the height of modernity.
What I like about Dulles - the glorious view of the Saarinen building as you drive up to it on a winter afternoon; the BA and LH lounges; the numerous non-stop international flights on a variety of airlines, certainly far more than one would normally expect for a city Washington's size;
What's OK about Dulles - Terminal B; Immigration and Customs - I know others have their complaints, but I have never had a difficult experience coming into Dulles, unlike both San Francisco and Chicago; the new train system;
What's I don't like about Dulles - Terminal C & D; they still haven't got the TSA setup to run efficiently, even after the restructuring (or maybe this is just a staffing deficiency); mobile lounges (sometimes)
While the mobile lounge system isn't great, I have managed to get from touchdown on an international flight to curb in 22 minutes - something that you would be hardpressed to do in a lot of other airports. Unfortunately, the mobile lounge system is more likely to be a bottleneck rather than the time-saver that it could be if they deployed enough of them.
Based on what people are saying about the airport, it sounds like it is worst if you are flying United (not necessarily because of the airline but because of its terminal), or if you are transiting. I find flying LH, BA, AF, and ANA to be a not-too-painful experience.