October 2013: It looks like this file became far popular than I thought! So I will keep this thread relevant for as long as I can.
As Blender progresses, the render settings found in this file will become outdated. The settings found in the above file might not be optimal for your CPU or GPU system. Adjust accordingly for optimal performance.
Download benchmark scene from BMW1M-MikePan.blend
Render and post result here
The result can be viewed from this spreadsheet