ESR and the MindCraft Fiasco
I think a contest would be better than a benchmark.
In a benchmark their are great odds that the benchmark will be sponsored by one of the party (M$ in this case).
If you do a contest, like the best ratio performance/price : you benchmark the performance of all the competing teams and then divide by the price the team involved in the hardware (not the software because due to Linux openness many people would say Linux price biased the contest).
If someone do so you can have a M$ team which will try to tune NT to is best, a Linux/Samba/Apache team which will try to tune Linux to his best, a Novell team, a Sun team...
You could choose your hardware so small team can try to compete. Even companies unrelated to NT/Linux/Novell/Another OS could compete so that can do a lot of publicity to these companies if they are well placed in the results.
It would be a good thing so every people supporting an operating system and so knowing how to tune it would be able to compete and their would be a greater range of results than in a single benchmark.
Of course we now need to find somebody to finance the contest :)