I have Falcon 4.0, never took the time to read the manual though, so never became proficient with it. I figure a video game with a manual that's thicker than the Bible is a little too much time for me. Got the game for free from a friend who felt the same way I do, so the addition of it being free probably adds to my unwillingness to learn it.
Along with F4.0 I have FS2004, X-Plane, and CFS2. I think if you're proficient with sims (good sims, with realistic physics and weather) you'll likely have a lot easier time swapping over to the real deal. I have some (very very little) time flying a Cessna, and from that I'll say there is a big step you can't re-create with sims, but in an emergency and lack of any certified pilot, I'd definitely rather have someone with a hundred sim hours landing my flight than someone who's never seen a cockpit outside an airshow.
Sims today are getting realistic enough to train with, I heard the FAA does train with X-Plane. They're definitely no replacement for real world experience, but you can pick up a lot I'm sure.