Yellow is fake gold; it's veneer and show rather than substance. We see that with the yellow cocktail music at Gatsby's party (1) and the two girls in twin yellow dresses who aren't as alluring as the golden Jordan (3.15).
I think a moderate income is income above the median for famlies in your county, but not more than 25% of the median income. The IRS usually has this info for free, but I see they are now charging $10 for this on their web site for more recent years. http://www.irs.gov/taxstats/indtaxst...=96947,00.html.
It depends on your lifestyle and how long you expect to live in retirement. By making certain assumptions, I'd say $2M-$3M is reasonable in the U.S. I will explain why. In the U.S., a single family can have a comfortable life with $60K-$90K annual pre-tax income depending on the area.