Interesting points being made on this thread. Personally I think General Aviation will continue to survive, despite what is currently going on (high oil prices, economic woes, environmentalism). Whilst I'm not old enough to remember the troubles of the 70s looking at history it does seem to draw parallels with today's problems... in the 70s there was tension in the Middle-East, oil prices went through the roof, economies were collapsing etc. Although as has been said it seems like today is small fry compared to what happened over 30 years ago.
For me it's hard not to draw the conclusion that this seems to be a cycle which is repeating itself again. Flying will unfortunately never be cheap, it never has been - it's not something which can be made cheap. Perhaps in 10-15 years' time we shall be looking back on today at the doom-and-gloom and wondering what we were all worrying about. There aigain perhaps I will be wrong!
Fuel prices I think are the main overriding concern for aviation as a whole, not just GA. Will oil continue to rise in price forever more? Are the days of "cheap" oil gone forever? It would be foolish to make a judgment now but I can't help but feel we have been here before in the 70s.
Personally I look forward to the future to see what it will bring... PPLs instructing; Corporate Aviation expanding rapidly; glass cockpits in light singles; I am keeping a watchful eye on developments with an open mind to see what the future brings for GA.