Milton Friedman
Gary Becker
George Stigler
Ronald Coase
&
collection of his writings
Douglass North
James Buchanan
Bob Mundell
&
his works
Oliver Williamson
Joseph Stiglitz
Other economists who are no less inspiring:
Robert Barro
(Harvard) and
his writings
Greg Mankiw
(Harvard) and
his popular blog
Ed. Phelps
(Columbia)
Steve Levitt
(Chicago) and his
Freakonomics
Kevin Murphy
(Chicago)
Robert J. Shiller
(Yale)
Brad DeLong
(Berkeley) and
his popular econ blog
Yingyi Qian
(Tsinghua)