This thread really shows that it depends on what you have to start and work with.We usually get away with adding topsoil/fill to build it up for drainage and get rid of any low spots.After it is compacted we dress the top with gravel or crushed clam shells.In swampy low lying areas people use railroad ballast mixed with fill dirt and compact that.I don't know the technical term for what we call "fill dirt" around here but it's the sandy layer mixed with fine gravel that is just below the top soil around here.Like Gully Washer mentioned sandy soils compact and drain very well.The stuff we have here compacts so well you almost need a jackhammer to break through it when properly compacted and other then in low lying areas it is rare they use anything else.