A couple of years ago I opened an account on istockphoto.com. Stock photography websites are (correctly) accused of devaluing stock photography in general, as every jerk with a DSLR can flood the market with lousy pictures with poor white balance and make $.01 per download. I am one of those jerks.
I have earned about $200 in sales from istockphoto, and the vast majority has been from a single photo of coffee beans I shot against some cardstock in my bathroom. Here it is:

It’s not even a good photo, but it’s been paid for 332 times — earning about a fourth of the cost of the lens that took the picture. Recently it occurred to me that my contract with istockphoto is non-exclusive, so if people want to insert my coffee bean photo into their PowerPoint presentations I should allow them to purchase it from a variety of vendors.
I signed up to be a photographer on Shutterstock and submitted the required 10 photographs, including the wildly popular coffee bean photo. Shutterstock indicated that they would review my initial set and get back to me in 2 to 7 days.
Four hours later, all ten photographs were rejected.
So if you are looking for a high-quality stock photography site, may I suggest http://www.shutterstock.com?