In the USA we have a minimum wage (currently not a LIVING wage, it's $8.75) and a "tipped employee" minimum wage. A waiter in a small diner will get paid $2 per hour, and depends on tips to live. So not tipping in the US is a slap in the face to the wait staff.
And yes, a very few restaurants in the US are beginning to pay their wait staff $15 per hour or more and advertise "no tipping". The food prices increase somewhat, which is of course offset by the fact that there's no tip to add.
We are taught that a 15% tip is standard. I teach my kids always start at 20% for good service, pay AT LEAST 15% on any bill, and if you feel that's too much, pay it anyway but talk to the manager and tell them why service was so bad. If the service was good, I'll round up - a $65 bill would usually get a $15 tip to make it an even $80. I have noticed that people who have ever worked in the restaurant industry are usually the best tippers.
Bartenders should be tipped separately. Usually, a minimum of $1 for any mixed drink - if a draft beer is $5.25, I'll give them $6. Bottled beers don't need quite as much, but give them something anyway. If you're ordering a $16 cosmo, give them a $20 and leave it. Remember - people without money will spend whatever they get, so you're helping the economy by keeping that money moving.