I'd heard stories about the MacBook Pro running pretty hot, since the aluminum construction basically makes the entire case surface a giant heatsync. So, when I got mine recently and noticed that it does run pretty hot, I went on eBay and bought one of those cheapy USB-powered laptop cooling pads. I staged a little test, and ran the laptop for 30 minutes each on the cooler, and one the bare tabletop. Using a handy little application called "Hardware Monitor", I pulled up a graph of the various temperature sensors. Much to my surprise, running the laptop on the cooler yielded higher temperatures on the CPU, GPU and enclosure. Leaving the laptop on a bare surface lowered the temperatures by about 5 degrees. While by no means a scientific study, it would appear that the aluminum case works better with a solid object to conduct heat to, than with the convection-cooling that a laptop cooler provides. Of course, the cooler I used (being a cheapy made in China cooler with poorly translated packaging) was plastic, though I have my doubts that a metal cooler of the traditional design would be any better. I think it would have to be more like an external heatsync, with fans blowing across fins, rather than the type that just blows/sucks air underneath the laptop. The reason I even bothered with all of this, is that I was originally going to purchase a set of "Apeelz" or some other similar protective skin to keep my prized posession from getting all scratched up, or just generally icky. This test suggests that I shouldn't, and that others should think twice about enclosing their MBP/PowerBook in a plastic skin. The likely result, is that you'll just suffocate it, since the metal case already provides sufficient cooling. It would be interesting to run such a comparison with a MacBook/iBook, since its plastic construction would conduct less heat. Just my thoughts; wanted to see if anyone else has come to similar conclusions.