Slashdot, the AP, and Sciam are all reprting on a new material for CPU’s –  Silicon carbide (SiC).  That’s the stuff used to make the heat shields on the Space Shuttle.  Although it may take a while, as “SiC semiconductors are generally expected to be put into practical use at around 2010-2012”  it does mean that you can look forward to a day when heat is no longer a concern inside your PC.
 

The problem with silicon — the basic building block of most electronics today — is that it becomes less reliable and less efficient when exposed to high temperatures or radiation.  Silicon carbide, which is so resistant to heat that it is used to protect space shuttles, is a semiconductor like silicon. It is also nearly as hard as diamonds.  But those unique properties make it difficult to use in electronics. Because it does not become liquid under high heat, it cannot undergo the traditional process that silicon undergoes that leads to nearly flaw-free chips.  The Japanese researchers discovered that they can build silicon carbide wafers by using a multiple-step process in which the crystal is grown in several stages. As a result, defects are minimized.