City-data.com

[jacob]

B_ suggested city-data.com as an efficient site to get the skinny on a place without having to live there.
Time to do some research ...

[AlexOliver]

the URL is: http://www.city-data.com/

[jacob]

Ugh! My bad. [corrected above]

[Cashflow]

Taxes by state:

http://retirementliving.com/RLtaxes.html
State-by-state guide to taxes on retirees (2009-2010):

http://www.kiplinger.com/tools/retiree_map/

[Cashflow]

Crime reports (if the police department provides such information):

http://www.crimereports.com/

[Cashflow]

Natural Hazards In Your Neighborhood (California):

http://myhazards.calema.ca.gov/
U.S. Geological Survey:

http://www.usgs.gov/

[JohnnyH]

citydata is great, but there is no good way to query variables of your choosing... It's frustrating the potential that you can't easily access.