I've had a lot of bikes in 35 years, and a lot of them (well, 4) stolen.
At home, or on the back of my truck, I use the Kryptonite chain, the thing is so solid and heavy it's almost hard to pick up, along with the fugghedaboutit lock. Seems about as good as it gets.
When it's sitting in a parking lot, I use my paid up full coverage insurance and hope, since you can't carry anything on your person that's heavy enough and thick enough to not be cut through quickly and your bike thrown into the back of a pickup truck in 20 seconds flat.