U-lock and a cable. Neither are very fancy, but together they offer enough PIA factor to deter theft. Never had a bike stolen or stripped using this method. Mind you, I'm not riding very expensive bikes and I'm careful where I lock up.

I usually put the U-lock around the rear rim and the seat stays -- it's a tight fit. Then I use the cable lock around both wheels. Now that I'm thinking about it and looking at Sheldon's page, I'm wondering if I'm not providing a good tight lever to break the U-lock with. But my logic is that even if they cut the rim they can't get the frame... no doubt over-kill.