Premium brand canned dog food like Merrick, Organix, Newmans, Wellness, etc, are surely edible and might even be tasty. However, they're also something like $3 a can so unless you're rich I doubt you'll be stocking that stuff up. JMO, but unless I was absolutely starving I wouldn't touch the non-premium stuff. Who the hell knows whats in there. There was a thread about pet food recently and someone posted a link to a company that makes dehydrated raw food. Looks cheaper than the premium canned stuff.

http://www.thehonestkitchen.com/index.shtml