IO540,
I agree that a moving map GPS when used properly is a great tool for VFR flying. It's not the only way to do it and "hiking" GPS can be used very effectively, again when used properly. As can good old fashioned visual nav. Like I said, it's the pilots that are the weak link in the GPS chain.
I am not sure how useful moving map is with full IFR flight. I am not sure how much heavy metal uses full moving map. FMS provides more than adequate "magenta line" nav, threshold to threshold, with terrain clearance being provided by planning, IFR, ATC and of course EGPWS. But that is not really relevant for virtually all private flying.