Dude, I had a bike stolen from in front of my kitchen window in my back yard, when I only stopped in for a couple hours, with the bike LOCKED to a gas line. It was a cable lock, and it wasn't even cut... it was pulled and mangled open.
Since then I have not used a cable for anything but locking wheels to frame. Only U-bolt or bar locks to lock the bike frame itself, no matter where it is. After that I got a U-bolt but my front wheel was stolen, so now both wheels get locked, as well as the seat and rack, no questions. Those are the main points of security for a bike. I also lock my helmet with the U-bolt, right through one of the vent holes. XD