Prepar3D + A2A Cessna or Piper aircraft + orbx scenery + Active Sky Next + Ezdok and you've got yourself a pretty good sim. You could spend a fortune on add-ons to make to look amazing and dont forget hardware, yokes and pedals can cost an arm and a leg.
Maybe worth Googling Dovetail games new flight sim that is coming out this year, from the looks of it its just a re-working and upgrade of FSX but we'll see.