http://www.grc.nasa.gov/WWW/RT1999/6000/6712chao2.html
This might shed some light on the subject...It has a graph to show the difference between aluminum/graphite and copper/graphite. Copper still beating graphite, but if you combine graphite and copper you have a very good heat conductive composite.
Also if I might add...a little off topic but...When you heat up a graphite hockey stick to replace the blade...the heat seems to stay localized to where you are heating...it does not travel up the shaft..just seems to penetrate through one way.
Tuff