I'll have to agree with P68 "it depends on the kind of work you do" I sincerly hope that no tail wind cancels out my head wind or myself!!
And on another theoretical note, why is it that we as pilots enjoy tail winds. I became a pilot because i enjoy flying. and a tailwind reduces the flying that i get to do.
However is it that we are slaves to efficiency, eg. I'm not going to fly slower than the best required speed for the sake of a few more hours in the long run.
Vote 1 for headwinds
ascj