Service, Tips, Gratutity, whatever you want to call it, it's not usually included on the bill in US restaurants. Sometimes in fancy places they add it on, but unless you are a large group or it's a special holiday or something it's not included.

The generally accepted practice is for good service to give 15%. If the meal was extrodinary, then you may want some additional money to go to the chef, but it's not all that common to see the line on the check for the chef. Excellent service you may want to tip more, Poor service you may want to tip less.

If you had a wine steawart or somebody else tend to your wine needs, you may want to tip them too.

There's a restaurant near the office in a very touristy section of New York (but it has very good food too) where they rubber stamp the checks in six languages that service charge is not included, just so nobody misses it.