Pace,
For me the most important benefit I try to get out of X-Plane is situational awareness, doing approaches or complicated SIDs or STARs. There are force-feedback yokes available for several thousands that will greatly improve the feel of flying even with the standard X-Plane programs. I have a friend who installed the PFC 'cockpit' similar to his Mooney in his cellar. It has three projectors on a curved screen, 'real' Garmins in the panel and a flushing loo in the corner of his cellar.
Maybe in twenty years we will be flying real aircraft with a mouse as well, the gap will become narrower then.