I actually enjoy shipping out of/into Dulles. I've had bad experiences at Reagan, and I can't stand BWI, so IAD is by default my favorite in the area. Direct flights to Tokyo and Beijing are also helpful

Yes, you have to ride the buggies, and yes, there is a lot of walking, and the C terminal needs some major upgrades around the lower numbered gates, but I can deal with all of those.
And the worst airport ever is O'Hare. Lost baggage... delayed planes... and the amount of time it takes to get through customs, take the train back to the main terminal, and go through security again... I'll do anything to skip that place.