I'm surprised at this thread. You guys aren't mentioning the obvious: Moore's law is just one of many paradigms. It's a bit silly to think that our chips will continue to utilize only 2 dimensions.
As Mr. Kurzweil has repeatedly said - Moore's law will run out of steam after we have established 3 dimensional molecular circuits.
/thread
The problems with 3d circuits are added manufacturing complexity and heat dissipation. While those can probably be overcome, that still may not allow moore's law like constant doubling of transistors within short periods of time. Once we can't make things any smaller, constant doubling of transistors will necessarily result in ever larger chips[which will be ever harder to manufacture and will require ever more energy.]. Performance can probably continue to increase regardless by finding alternate small structures[atoms|molecules|etc] that can perform logic that would require say X number of transistors to implement, and using such instead of X transistors.
Making ever larger chips is unlikely to be viable manufacturing-wise in a cost-effective manner without some form of advanced molecular machinery[say synthetic bio or nanotech] to allow for precise and cheap manufacturing almost independent of size|complexity.