Robin Hanson's Home Page has some
very thoughtful economic insights.
Tom Bell (aka Tom Morrow)
Ralph C. Merkle has some papers on cryonics, nanotech, and
cryptography which are as cool as liquid nitrogen.
"David D. Friedman's Home Page"
If you are looking for something unusual, Anders Sandberg's home page
is the place to start.
Nick Szabo's Home Page
Ted Kaehler's Homepage
Greg Burch's Home Page
Eric Raymond's Home Page