What is an appropriate amount to tip for taxi driver?

10-15 percent of the total fare...dont be cheap! It is an American custom to tip and a lot of workers rely on those tips for their livelyhood...

Less then you would tip a waiter or bartender, but 10% is about normal. However, much like other forms of tipping, it has become to expected by the server to get tipped. They sill have to provide good service. I have run into the rudest and worst driving cabbies in the world , and I dont see why we should ever tip them if they are likee that.

In most cases 10% would be perfect though. 15% for a good job.

15% of the amount on the meter, is what I've always read to be the "standard" tip. More if the driver was nice, polite and even offered touristy info, less if he was curt, rude, and deliberately took the long route.