It's been said before but your best bet is to use a couple of different systems.
Some fat-neck, pikey, scum with no right to exist on this earth tried to lift one of my bikes from in front of my house. They popped the two very substantial (looking) chains but didn't cut the cable lock. They squashed it and frayed it but couldn't cut it with bolt croppers. If they had spent some time with some electrician's side cutters they could have nibbled through it quite easily I'm sure but luckily they didn't sus that.
Locking the brakes on works quite well if they have to get it some distance to their van.
A few years ago, one of the bike mags did an article on theft. They parked a bike in a town centre for a few hours then turned up with an un-marked van. They used a petrol disc cutter on the chain and then lifted the bike into the van with the alarm going and weren't challenged.