Okay, well maybe top 10 is a bit of a misnomer, since these are just 10 free and public domain stock photo sites that I find useful from time to time, but the list still applies. Everything on these sites is free at no cost to you, though please do check the rights on each image, as they may be licensed under a Creative Commons license that requires you to give credit to the photographer.

1. Public-Domain-Photos.com
   Has both photos and clipart, for apparently almost any use - personal or commercial. They have a decent sized portfolio to choose from, and all photos are categorized pretty well
2. Image * After
   Contains a ton of free images, as well as textures. Everything’s categorized well, and they have a unique “Color Chooser” that picks out photos that match the color you choose.
3. Stockvault
   Stockvault touts over 8,000 high resolution images free for download. If you feel like sharing your own photos, you can sign up for their revshare program which allows you to put your own Google Adsense on the pages they feature your photos on. Nifty!
4. Stock.xchng
   Boasting over 250,000 images and 25,000 photographers, I believe Stock.xchng is one of the biggest free stock photo sites on the web. They have a great layout and it’s easy to find what you’re looking for. Personally, I start here.
5. Yotophoto
   If you know what you’re looking for, Yotophoto might be the place to find it. They have a simple, easy to navigate layout and a powerful search tool to find just about any free photo you’re looking for. Also a big thumbs up.
6. Flickr’s Creative Commons Directory
   This is the big one, folks. Flickr’s one of the biggest photography related sites on the internet, and everyone can have an account (<3 Flickr). The big deal here is that a lot of people have chosen to share their images with the world under various Creative Commons Licenses. Take a look, I guarantee you’ll find something worthwhile.
7. FreeRange
   FreeRange is a bit like Yotophoto in that it’s primarily for people who know what they’re looking for. The search works, but perhaps a little cleanup on their results page would be nice (better details would be helpful in any case).
8. Flickr’s Stock Repository Group
   Leave what you can, take what you need. Make sure to give the photographer a heads up when you use something, but otherwise go for a browse - there’s some good stuff here.
9. morgueFile
   While it doesn’t seem to have an incredible number of images, what photos it does have is high resolution and requires very little cleanup. Take a look - they might have what you need.
10. PerfectPixelDigital
    Very much like morgueFile, this one doesn’t have a ton of images, but the layout is clean, easily navigable, and they have some really nice shots.