We always tip 15% for normal table service and 20% for exceptional service.
We also do the same for buffet-style meals, if the waiter or waitress has been friendly and brought us lots of coffee etc.
I've read that in some cases, the IRS (U.S.A. Inland Revenue) taxes these workers on the assumption that they receive an average 15% in tips. This was confirmed by a waitress we talked to at Finnegan's restaurant in Universal Studios. She also said that a percentage of her tips were given to other employees, such as the kitchen staff member, who brought the main course to our table. When we asked whether the girl on the counter received anything, she replied: 'Oh lord no! We don't have to give anything to her! Looks like poor old counter-girl is bottom of the pecking order then.
Steve.