We currently offer a massive range of downloads for FSX, as well as older flight simulator add-ons for the ever-popular FS2004, FS2002, CFS3 and now becoming ever popular with dediced virtual aviators is Laminar Research's X-Plane series.
It moves like a jet, it moves like a helicopter but it handles like neither. By far the most challenging aircraft to fly it's also the most fun. Short takeoff and vertical landing (STOVL) hover it, fly sideways, land at 3 knots. It looks and feels great in Microsoft's Flight Simulator X