Looks like an old thread, but perhaps locking a bike is still pertinent.

I've used an OnGuard combination cable lock for years. It seemed ok. Some of the plastic cowling has fallen off, but the lock is still good. Unfortunately, I'm seeing more and more signs that people are going after cable locks, so I've decided to put it into semi-retirement.

So, I'm now using a Kryptonite NY U-lock. man is it heavy
My only complaint is that the key tends to stick at the 90° point, and it needs to be turned to 180°. Otherwise it works well (so far).