If you are comfortable and happy working in a Unix/Linux environment,
the answer is yes. I am not sure that I would recommend that a Windows
user switch to Linux64 on an Opteron just for the speed improvement--it
might be too much of a culture shock for them.
Economics is (as is sometimes not so apparent) a behavioral science. An
economist would include in the cost-benefit analysis not only the cost
of the cultural shock of a Windows user (and the ensuing short-term
loss of productivity) making that move, but the benefit of the likely
increase in their life expectancy due to a reduction in the probability
of apoplexy following the repeated assaults on their system by the
inevitable horde of viruses, worms,... It's sort of like the
high-cholesterol person choosing to eschew unhealthy fast food -- it's
a lot more effort to eat healthy meals (especially if you have to cook
them!) but you will live longer to enjoy them.
