This interesting and concise study
by the Federal Reserve Bank of St. Louis is worth a read.  It does
an excellent job of explaining the difference between a private and
public good and using this difference as the distinction in
understanding a “public use.”

It also explains why economic development takings are bad for economic development.  From the article’s conclusion:

“Supporters
of Kelo argue that using eminent domain for private development will
spur economic growth. Although a lack of sufficient data currently
prevents empirically testing the economic effects of eminent domain
described in this article, economic theory certainly suggests that
eminent domain used for private economic development will likely result
in a zero-sum gain and may actually hinder economic development in the
local areas, as well as the region, rather than help.”