There was a poster, who I will not name, deleted his post but I thought it was actually quite good. In it he said he uses a cable lock and has never had a problem and others thinking about this sort of stuff like picking or angle grinder, etc are just plain paranoid. I agree...to some degree. I think in most cities and towns in the US there is no need to have a fancy $150 lock and those that do it's plainly paranoia. However there are exceptions, I know that many universities and colleges are huge targets for bike thieves, and some very large cities most notably New York, if you live in those areas you should be paranoid! And if you live in an area that makes you paranoid then you should seriously consider taking either a nice used around the $250 mark for a bike or a Walmart special and lock it up with a decent lock but nothing expensive. All I have used in several cites I lived in was a thick cable with a Abus Discus lock for the last 40 years. When I was going to college I bought a Schwinn Traveler and left the good bike at the apartment, and that bike was never stolen, though people around me had theirs taken while I used nothing but a cable lock.