the kryptonite new york series is pretty high-end, and a chain/U-lock combo is the gold standard for cyclists. if you're going to be locking up at one set location then weight shouldn't be an issue and you can double up like that.

if you really want to go nuts, the hiplok D1000 is considered "angle grinder proof" because it'll wear down a cutting disc before you being able to cut all the way through it. really though, you don't need the best lock around--you just need a better lock than the person next to you.