I use an On-Guard Mini ulock which is the same size as the Krypto mini along with a cable.
I use racks here in boston almost identical to those nyc city racks.
With my mini U lock I can lock my back wheel (inside the rear frame triangle) to the rack pole, but there is not enough space to fit the rear frame in the u-lock. I whip my cable through the front wheel and into the U-lock. As for my seat, I took it inside with me for a long time, since my cable is too thick and too short to extend though my seat rails. Then I found a bike chain, wrapped it in an old inner tube, and secured my seat to my frame with it. I no longer worry about my seat being stolen.
The rear triangle method.
A thief must now have three separate tools to steal my entire bike (one for the cable, one for the U-lock/rear wheel, and a chain tool).
Also, don't rely on security cameras to offer any security.
http://www.youtube.com/watch?v=y-0DyHc5lms