The large number of people having difficulty with FSX v framerates, stutters and blurries, have cured them only by going to dual core processors I bow to the masses.But currently I have none of the above problems with my system. But then I have FSX turned right down to about 25%, any higher and FR's will be hit, as for blurries and stutters, almost non existant. But again, I am running a default setup, GenX is still in the box.
As far as software goes, it takes years for M$ to rewrite Office, admit the gaming houses are more on the ball, but how many of the games, in the last 12 months, boast compatiablity with dual/quad core and SLI/Crossfire? It is your everyday type software that lags. Not that they need that muscle.
But yes, we need to future proof, otherwise end up spending forever. It is like changing your car for a new one every 2-3 years, the models get better and better, but they still do the same job.