Originally Posted by FliesWay2Much
I agree with the last poster who recommended PHL as an alternative. For the itinerary you're interested in flying, I can't think of a general advantage of BWI over IAD in terms of fares and choices. There may be specific advantages depending upon where you want to go. I would stick with BWI or PHL as an alternative unless there are compelling reasons to go to DCA or IAD. I define "compelling" as a fare out of one of these aprports being hundreds of dollars cheaper.
If you have to have a second airport, as was already said, PHL is much better than the DC airports. That said, if you leave your office by 4pm, you're still going to be in Wilmington, DE traffic on the way to PHL. Keep that in mind. So I think your best bet is BWI. You can beat the crux of the Baltimore rush hour if you go there.