What Dorf said - sound orientation, tracking and intercept skills using dials are a great basis for being able to deal with different types and equipment fits, and for handling emergencies when the screens fail and you have to revert to standby instruments. That doesn't mean you should ignore glass cockpit type equipment, but rather than learn on that and be baffled by 'steam driven' instruments, my view is that if you learn to be competent old-school, you can fairly easily migrate to the new world (lots of great educational resources on the internet from Garmin etc to allow you to play with the newer gear, learn the menus etc without having to pay for it).