I use the Sheldon technique and a wheel cable because I'm also in a low crime area. Never had much of a concern about it.

With the "how to lock a bike" link, the only additional suggestion I have is to put the front wheel between the bike and the post when locking through, instead of on the outside of the bike. Leaving it outside the bike is just one more thing for someone to randomly walk by and mess with just for the sake of messing with someone's stuff. Sandwiching it between the frame and the post makes it more difficult to screw around with.