It doesn't really matter. Beware though if you are going to use it, and are going to let SW boolean join some meshes together when your model gets uploaded, there will be a discrepancy.
Bigg news though!!! Blender 2.65a release has an option to move the origin to the center of mass, which is the same thing. Do this in object mode from the tool panel.
Last edited: Dec 25, 2012