As already mentioned theres only so far you can go with Silicon, Just think how fast some of the next gen chips will be, some of the articles I've read mention:
DNA computing
Quantum Computing
(see
http://www.newscientist.com/hottopic...p?id=22901400)
Optical Computing
Molecule Cascade techniques (create tiny Babbage engines???)
(see
http://www.theregister.co.uk/content/3/27778.html)
Talkie Toaster could be closer than you think [img]smile.gif[/img]