Desktop flight simulators (e.g. IL-2 or Microsoft's Flight Simulator) work amazingly well, all things considered. There are, however, a number of major problems. The two greatest are lack of view area and lack of rudder pedals. The former is exacerbated by the need to display the instruments on the monitor as well as the outside world.
In order improve the situation, I invested in some "toys" recently. The rudder pedals are fairly straightforward, but the view area problem is trickier. I don't have room for dozens of monitors or a giant projection system, but a head tracker seems a reasonable solution. This measures the position of your head, and adjusts the view angle accordingly. As it is a six axis device, you can even lean to one side to see around a pillar, or move forwards to get a better view of the instruments. It takes a bit of getting used to, and does demand that you wear a cap with special reflective tabs on it. Head movements are exaggerated, so looking (say) left doesn't demand that you turn your head sideways to the monitor. This is handy, as otherwise you wouldn't be able to see it!
See TrackIR and Pedals for more details if you are interested.
My friend Nigel is determined that I should take up the hobby of aeromodelling. He is so determined that he has even let me fly his models from time to time. I'm not sure who more more nervous – him or me! So far, I've managed two landings. The second was much better than the first. Mind you, that wasn't particularly good!
It seems very strange, controlling an aircraft when your point of view is so different from that of someone seated in it. Another problem is the lack of airspeed indicator. This makes me very nervous of stalling, which in turn makes it hard to fly slowly enough to land. It seems that FMS (above) is a useful training aid. It does give some experience of both these problems without risking any damage to a model.