Tipping is such a highly contested issue around the web. Here is a good guide to tipping your wedding photographer and Videographer. You can read the rest of the post, which will have more info on tipping your other pros HERE.
Photographers and Videographers are two vendors whose actual work you wont see for weeks if not months after the events. You see them busting their butts that day to get that perfect shot from the top of the hill, and of course you see them herding your family into group shots. You don't see the hours and hours of slaving over their computers, the THOUSANDS they spend on equipment and digital sites to house your media. My recommendation, when I do wedding planning, is to tip them for the work they do the day of, and their on-site service that day. Then, if you're particularly happy with the result, and if you hired the right pro, you should be, tip them after. I usually recommend for a photographer you spent $3500 on, tip $100-200 on the day of, and do that again at product receipt. That can vary, of course, if you spend more, tip more. Think of this in hours worked, as well. Many photographers spend 10 hours on the day of, and another 10-20 hours editing, uploading, creating albums, etc. They too, are in the service industry.
The Knot says this about tipping...