First time I went to change my oil, I found that the drain plug had been installed by a gorilla. Even using a good quality 6 point socket, the corners just crumbled. A member on another forum suggested using the Sears Bolt-Out. I was sceptical but it worked great, it took over 95 ft lbs before it loosened.
http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=00952166000
http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=00952166000