I was out walking the girls and ran across this guy. It was getting dark and since I had them, I couldn't really investigate. At first I thought it was a copperhead, but I've never seen one of those stand up like this. Bad pics, but I couldn't get closer. When I look at these, it looks like a rattler of some sort. It wasn't rattling when we walked by it.
EDIT: I'm still thinking copperhead... But, like I said, I've never seen one of those stand up like this.