Hm.... this isn't going to be a popular view here... but I'm not a fan of expensive locks.
I tend to park my bike in public areas, near shops or post offices (or in my office) where people come and go frequently, and I've never had my bike damaged or stolen. I kinda look at it in the same way as computer viruses: a modicum of backup, just in case, but on the whole a bit of common sense will steer you clear.
In my view, a lock isn't much of a deterrent unless it is part of the bike itself (a bit like a car lock) which when broken would make it obvious it had been stolen, and relatively expensive to repair. Unlike the example above, which could be relatively easily covered up (or prevented from causing damage at all by a savvy crim).