A website for stock images

As a designer I am always looking for images that I can legally use in my layouts. I know that you can not download images off a website or scan them out of other print material to use in my layouts. If I did not take an image myself, I need to find a stock image that I can purchase the rights to. Through the years I have found a reasonably priced website that is a critical tool to what I do everyday. iStockphoto.com is a great website with a wonderful selection of photos. I hope that you find it as useful as I do.