Update: I was unfortunately not aware of Shamus Young's severe criticism of Fallout 3 available here to link in the original piece and I regret that. It dovetails rather nicely with what I've written and it's much better executed than my piece. I strongly recommend anyone...
X-Plane is the world's most comprehensive, powerful flight simulator, and has the most realistic flight model available for personal computers.
Welcome to the world of props, jets, single- and multi-engine airplanes, as well as gliders, helicopters and VTOLs such as the V-22 Osprey and AV8-B Harrier.
X-Plane comes with subsonic and supersonic flight dynamics, sporting aircraft from the Bell 206 Jet-Ranger helicopter and Cessna 172 light plane to the supersonic Concorde and Mach-3 XB-70 Valkyrie. X-Plane comes with about 40 aircraft spanning the aviation industry (and history), and several hundred more are freely downloadable from the internet.
X-Plane scenery is almost world-wide, with scenery for the entire United States, Hawaii, Alaska, Europe, Australia, Canada, and Japan on the CD, and more scenery downloadable from www.X-Plane.com. You can land at any of over 18,000 airports, as well as test your mettle on aircraft carriers, helipads on building tops, frigates that pitch and roll in the waves, and oil rigs.
Also updates the game if you have the retail version of the game. The new 8.x range of releases offer several new features.