What is the best bicycle lock money can buy?

Here it is:

Kryptonite New York Fahgettaboudit U-lock, $89.95
Pertinent Thickness: 18 mm Shackle
Weight: 4.6 pounds
Free Anti-Theft Warranty: $4,500 for one year
If I were a pro bicycle thief, I'd skip any bike protected by a poison-frog-yellow New York Fahgettaboudit U-lock (or the NYFU). It took its beating with the poise of a journeyman NHL defenseman. At my hacksawing rate, it would have taken 42 minutes to cut through the 18 mm shackle. (It didn't get a perfect 20 score for security because my assault managed to jar a spring loose inside the crossbar, but that wouldn't affect lockup strength.)

Kryptonite u locks. I had to try to remove one once. You can't saw it, you can drill the key hole, but that doesn't do anything, it bent my car jack trying to pop it off, finally I borrowed an angle grinder and that took about 10 minutes to cut through it. There's no better lock. I'd probably save my money and get a mid-level kryptonite. Any heavier and it would be much easier to cut whatever I locked it to (and it would cost me another $50).

It's expensive, but you can raise a mean pit bull in a year or so, and put him on guard by your bike. An actual bike lock is cheaper, though. :o)

A pit bull will work fine, but a human guard is even better... it's just tougher to carry around.

EVERY lock can be defeated.

Its not buying a bike since then you don't have to lock it up