:drink: The actual refresh rate that your eyes are exposed too is dependent on the the display hardware and its driver settings not what your GPU is telling you (FPS).
My 24" SyncMaster is restricted to 60hz while the small LED ASUS will refresh up to 75 Hz & the advertised responce time for any given monitor is a weighted average and is often overstated, and dependent on the colors involved.
As display tech is rapidly changing any thing we read can be old news tomorrow but any thing above 40 Hz for a flight Sim is good. For First Person Shooters it would only be adequate.
PS If your interested this is a good article even though its a few years out of sync http://www.tweakguides.com/Graphics_1.html