What is the cost of living difference between San Francisco,
California and Berlin, Germany for a married couple without children. 
Please provide supporting documentation.  Thank you!

This chart shows comparitive costs of living for various countries:
http://www.expataccess.com/i/ea/cost_of_living.html

It gives an index for each country - the relative increase/decrease in
cost of living is the index of the city you're moving to divided by
the index of the city you're moving from.

Berlin has an index of 135, while the average US city has an index of
100, meaning the cost of living in Berlin is ~35% higher than your
average US city.  Of course, San Fransisco is not your average US
city, now is it?  :-)  If you go to:
http://www.homefair.com/homefair/calc/salcalc.html

You can compare costs of living in various US cities.  Comparing the
cost of living of, say, Chicago to San Francisco reveals that there is
~35% increase in cost of living from Chicago to San Francisco, a 30%
diff. between Boston and SF, a 98% difference between Atlanta and San
Fransisco, etc.  So one might expect the cost of living between your
"average" US large city and San Francisco to be in the neighborhood of
50%.  In which case we'd have a 135/150 ratio from moving from SF to
Berlin, meaning the cost of living would decrease by about 10%.

Some other Web pages to check out that may help give you an idea of
the cost of living differences between the two locales.  This page
(http://www.cityguide.travel-guides.com/cities/bel/CostofLiving.asp)
gives a few examples of what it costs to do typical things in Berlin
and how much it would cost in correspnding dollars; you may want to
check out this page (http://www.ecis.org/directory/CountryInfo/Germany.html),
which highlights various issues of working and living in Germany
(taxes, the culture, housing, etc.).

I think you'll find that certain things in Germany will be a lot more
expensive that what you're used to paying (gasoline, for example),
but, compared to San Fransisco, the house prices in Berlin will seem
low (maybe $2k / month to rent a 2-bedroom house in the suburbs of
Berlin).

This was helpful, as I am considering moving back to SF from Berlin. 
However, in my real life experience, I found that the cost of living
in Berlin is about 50% lower than living in SF.  However, the tax rate
here in Berlin is effectively 51% all included, so perhaps a 25%
difference is more realistic, if tax is accounted for.  By the way,
$2k/mo. for a house in the suburbs of berlin will get you a mansion. 
$2k in the center of berlin gets you at least 3 bedrooms or a very
high quality 2 bedroom.
However, the question was answered very quickly and clearly.

Hello, you may find this website useful The Riley Guide: Targeting &
Research: http://www.rileyguide.com/relocate.html