W18 -- Laurel-Surburban, in Maryland. Well, it's short, narrow, and obstructed. It's also tucked into a fairly narrow slot between the BWI Class B surface area and the FRZ no-fly zone around Washington, and within the ADIZ. It's kind of hidden in the trees, too. All in all, not for the faint of heart. If you go there, be sure you get the Baltimore-Washington Terminal Area Chart along with the Washington Sectional so you can a) find it and b) stay out of the FRZ/B-space. All in all, Tipton Airport (FME) is probably a better choice if you've never been into W18. It's longer and wider, its runway surface is in in better shape, and it's farther from the FRZ (four miles rather than two).
But whichever you choose, know the ADIZ procedures cold, follow them explicitly, and whatever you do, don't squawk 1200 in the ADIZ even if the controller absent-mindedly tells you to.