John,
The flight simulator I use (vicarious flying for a guy who cannot pass the FAA physical to be a real pilot) is
X-Plane. It is the only option for the Mac today. Runs pretty well on the old Beige, thanks to the massive video card. Frame rates are 16-18 fps at 1024x768 with the detail level set one click under "max."
A good desktop flight sim is like real simulator training. I can plan a flight, and have to use the same navigation aids as a real pilot to get from A to B, all in real time. If your landing technique is not good, you make 1/18th of a golf course. It can be set to randomly cause some systems to fail in flight. It can be as simple as the autopilot going walkabout, or as serious as having a wing fall off. A good mark of proper sim programming is that all the planes should not "feel" the same. A big jet should not feel like a Cessna (this is a complaint I've heard against MS Flight Simulator).
Jim,
I'd love to have all those control input devices but they are way too expensive. I have a single Saitek joystick--no rudder pedals. There are thumb buttons on the stick that I've programmed to control the rudder. Even if I could afford the pedal and yoke sets, I believe my USB card is not going to tolerate any more widgets. With the vid card, I'm reluctant to add any more PCI cards. I believe the big Radeon is drawing a bunch of electrons from the PCI bus.
Allan