With the relatively recent advent of cordless angle grinders, no lock is really good enough any more. I also just carry a few ounces of cable/combination lock and depend on situational awareness. And flexibility. I always keep my money and ID with me. Ditto the above: I also ride an old replaceable bike with old replaceable gear. If the bike gets stolen on tour, it'll probably be in a city with an airport or bus station and I'll go home and start again with slightly newer stuff.