I am about to compile a free and paid list of stock image sites.
I am no way afilliated with any sites listed. Other then being signed up at sxc.

Free:

• www.sxc.hu - - - » With over 87000 photos online. Large free stock site where users submit photos. The only one I use.
• http://www.freefoto.com
• http://www.imageafter.com/
• http://www.morguefile.com/ver3/

Paid:

• http://www.gettyimages.com/
• http://www.corbis.com/
• http://www.comstock.com/

Sorry if this list isn't good enough. I will keep on adding anytime I find a stock photo site.