Interesting...
Doing a quick Google using the term, "how much to tip in the US" I came up with the following links:
http://www.onlineconversion.com/tip_calculator.htm
http://people.howstuffworks.com/tipping2.htm
http://money.cnn.com/pf/features/lists/tipping/
http://www.ehow.com/how_112004_tip-properly-north.html
http://query.nytimes.com/gst/fullpag...50C0A967948260
This one has some interesting info about how much to tip around the world
http://www.budgettravel.com/bt-dyn/c...010200816.html
I say, interesting, because each one of them suggests that a tip should be 15% to 20% (where 15% is regular service and 20% is exceptional service). I realize this not a scientific sampling but it would seem that everyone who tips 20% for regular service is over tipping.
I would suggest that those who are upset when people don't regularly tip 20% should, instead of whining about it, actually attempt to change the meme. Start calling the publishers of guide books, travel agents, tour operators, etc. And let them know that they are giving out erroneous information. The tip rate has gone up and they are doing a disservice to legions of waitrons...
Just a thought.