This website is fantastic. www.creativeuncut.com
This guy collects Video game design artwork and keeps a large and ever growing database of his findings. I've been following the site for a few years, the layout has changed a few times (i was a bigger fan of its previous layout), but the updates have only been coming more frequently. Now its updated on a nearly daily basis. He even has an open door policy with sharing his collection (he doesn't even put hideous watermarks on them). What a nice guy.