This should buy you lots of noise and cutters longer than 1m:
http://www.abus.com/eng/Mobile-Security/Motorbike-Scooter/Lock-chain-combinations/Granit-Extreme-Plus-59Make sure bike is locked to something immobile, through the frame, above ground if at all possible.
Good lock (hard to pick), good, hardened steel - all the way to the core, not just surface hardened that is easier to cut.
With electric grinder, or big bold cutters, it will be cut - in under 10 minutes probably, but it will need noise, good tools and longer than most other (cheaper) chains.
Disk locks are not good when your bike gets loaded onto a van - like most bikes get stolen where I live, while alarm is good for kinds not sitting on your bike, not much more.
EDIT: Video from 3 mins onwards, thanks Darrsi, forgot to mention.
My fazer was locked and with an alarm - and dragged 20 meters away by one strong man. He wasn't about to steal it, just relocate, fortunately.