I only lock my bikes when they are on the bike rack on my car; then it's two cable locks that go through both bikes, each other, and the rack, plus two u-locks. It would be far easier to simply steal the vehicle. Otherwise, my bikes are indoors. If I lived in NYC, my street bike would be either a beater or disguised as one and I'd use multiple locks, cables, chains, grenades, rottweilers, whatever it took.

Where I live, though, people leave bikes out in the front yard, driveway, porch, etc. unlocked forever. Down at the local pool, some old man left his commuter bike there for a week and a half. I felt sorry for it. He came and got it and still rides around the neighborhood.