One of the things I think that makes a Well-Met man is tipping appropriately. That means tipping well. I will get onto regular tipping etiquette in a few, but here is a new article I just saw that is something I never thought of - the benefits to the service person of tipping in cash even if paying the bill in plastic. Read the article and think about it next time you go out - make sure you have cash on you for any tips.
Back to tipping etiquette in general. Common knowledge is to tip at 15%, however I am a firm believer in tipping well in most situations. For wait staff for example, I usually go right to the 20%, and may go down to 15% for less than stellar service. I also don't believe in statement tips. Either tip or don't. Make a statement by not tipping, not by leaving say 5% or just a dollar bill as the tip. If you really had that bad of service, do the person, the business, and future customers a favor and talk to the manager instead. You may get something out of it. And don't talk to the manager just to try to get something such as a discount on this or a future service.
Now when there isn't a cost to the service, the cost is high so a tip would be extravagant, or other odd situations, there is standard etiquette on how to tip beyond the 15% rule. Here is a web site that lists standard tips for various services such as $1 or more per bag at the airport, and $10 for bringing you to your room with luggage plus $5 dollars for opening and showing the room to hotel bellhops. A special page is set aside for Holiday tipping - tipping people such as newspaper delivery person for their year of service at the holidays.