Usually a U lock and cable lock in a rucksack, but I have a Nitto front rack which is yet to be fitted and then the locks can go in a bar bag. The 600 AX brakes don't leave much space between the calipers and tyres for the rack attachment, so some fairly precise cutting and drilling will be next on the list.
I usually sit at an outside table at the pub where I can keep the bike in sight (and gloat a bit). The bar staff can see it through the door when I go to the toilets and they watch it for me (and earn good tips), as do the other regulars.
The cable lock is 6' long and coils up. It fits through the saddle rails and the rear of the frame and wheel and the U lock fits through the front wheel, frame and parking sign that I lock it to.I also have a long hasped padlock that fits through the spokes and rear triangle. When our bikes are parked at home, we lock them all together with multiple locks.