I just bought a new, improved version of On Guard's Pitbull Mini. My 5 year old NYC Kryptonite was starting to jam. The Pitbull mini seems solid and the key lock portion seems improved. I have a GT Hybrid but I can't lock my frame and rear wheel to the rack. Has anyone heard or read anything new concerning whether or not the "Sheldon Brown" locking method works? I guess I should state that I will be locking up on the mean streets of Chicago which has a very high rate of bike thefts.

unless they cut through your rim and tire somehow or cut your frame (or the lock, duh) then it should be fine

Yup it works. It would take a criminal 2 tools to defeat both kinds of locks, so they are more likely to move on to an easier target. If you are in a high crime area, you should get a strong cable to go with your U-lock, and lock down your seat post as well.

Angle grinder works just fine on a U-lock and cable locks. And it'll do a number on a wheel, too. And, yes, depending on where you lock up in Chicago, and when, and for how long, and how nice a bike you have, there are thieves who will cut a wheel to steal a bike.

Well, if your thief is carrying an angle grinder and is willing to cut through your wheels on a public street then you have no shot anyway. Most U-locks are defeated with a crow-bar though, while a big cable normally requires a set of bolt cutters. But anyone stupid enough to cut through wheels is just getting a frame anyway, and what's a typical used commuter frame (not carbon) worth on the open market? Fifty bucks? Seems like a helluva risk to go through for that kind of money. One reason not to overspend on your commuter in Chicago I guess.