i disagree. unless you live in fairfax or w. montgomery counties, iad is the least convenient of the 3. imo, the convenience of dca easily offsets the no-pee rule. bwi is pretty ok too, particularly if you live near a red line station. unlike some of the others here, i've never had any problems with the train-->bus connection at bwi rail station (there always seem to be vans waiting when i get off the train).