Um locks are old school. Any portable cut off saw with a diamond blade will cut that little lock in about as fast as you can get to your garage.
No lock is impenetrable so what is there?
Well there is GPS.
There are small little devices you can put inside your frame
to track your bike when it's stolen.
It can even send you a text while it's being stolen.
Then you can call the police and have them handle it.
But, these have significant limitations, as well. Aside from recurring costs for data transfer, there's this: "Because it relies on GPS, the device will stop operating effectively if your bike is taken inside or anywhere there isn't a clear view of the sky. In that case, the unit will step down to GSM cellular triangulation. The company says GSM is only accurate to about 650 feet (200 m), which could prove all but useless in a building-dense environment like the center of a city. In fact, even GPS's claimed 16 to 82 feet (5 to 25 m) accuracy won't necessarily bring you right to the thief's doorstep." (source: http://www.gizmag.com/spybike-gps-tracker/22999/
Seems to me that, if you can't keep the bike with you, take off a wheel, use a very cheap and light weight cable lock, stay in sight of the bike and buy a $40.00 Kimber Pepper Blaster. When the thief is caught in the act, give him a message that keeps on giving for about 45 minutes, at least (suggested with the usual disclaimers)