Are there vibrations or any other symptoms while driving? Does the humming get louder as speed increases, or do you hear the humming only at a certain rpm or speed?
My guess would be a bad bearing or unbalanced wheel, those are the only 2 times I had a humming sound coming from a wheel while Iā??m driving. With the unbalanced wheel my whole car was shaking but only around 55mph. With the bad bearing the humming was there the whole time and it got slightly louder as speed increased.
Never had any experience with a bent driveshaft on a Contour, but on my parents van it caused the whole van to shake and the humming was unbearable.

95 SE MTX DH UIM, 65mm TB, SC CAI, Quaife, Centerforce, Fidanza, UR Pulley, F/R Strut Braces, Cross Drilled Rotors, S.S. Brake Hoses, 18" Enkei RS5, SVT Engine Mounts+Inserts, MSDS & y-pipe, Trubendz resonated exhaust & MagnaFlow cat