I finally got around to reading Eaton and Cordain's "Consideration of
Common Counterarguments" which can be found in the articles section of
www.thepaleodiet.com.  Absolutely fascinating reading!  Following are the
counterarguments and replies:

Moderns Live Longer - True.  But even factoring out the fact that infant
mortality brings averages down, increased life expectancy is primarily due
decreased risk of infectious disease, a very recent development.  "The
adoption of farming and settled living is commonly considered an advance
for humanity, but the new conditions appear to adversely affected
longetivity, precipitating a substantial decline to about 20 years.
Mortality profiles thereafter remained relatively stable (as late as 1667
average life expectancy in London was estimated to have been 18)."

Longer-lived Populations Naturally Manifest More Age-Related Disease - My
father's favorite argument against paleo.  If paleo man had lived long
enough, he too would have had heart attacks, strokes, and cancer.  Problem
with that argument, Eaton and Cordain say, is that "comparison of
age-matched younger members of industrial and technologically primitive
societies" show that biomarkers of chronic degenerative disease (obesity,
rising blood pressure, nonobstructive coronary artherosclerosis, and
insulin resistance) are "common among the former , but rare in the
latter."

Man Has Changed Genetically Since Agriculture - "If agriculture and
'civilization' have significantly altered the human genome, groups like
the Kalahari San, arctic Inuit, and Australian Aborigines...should differ
genetically, in some systematic, identifiable way from Near Easterners,
Chinese, and New Guineans.... There is no evidence for such distinction."

Diversity of Ancestral Environments - "...differences between ancestral
environments across time and space were minor compared with their
essential similarities."

Human Adaptability - Mere adaptability, while obviously a positive
characteristic, doesn't mean that an organism is living in its optimal
environment for which its genes were selected.