Below is a picture of a PE line to shock leader knot. The pic is via Nigel from http://www.fishingjapan.net/ and it is his translated version from the original Varivas version that was in Japanese.
I have been snagged a couple of times on the bottom and this knot stays intact even with no drag set when I try to break it off. It's very difficult to even break the line off with this knot (one time the hook bent out before the line or knot broke).
I use 20 lb PE and 30 lb Varivas shock leader. I have total confidence in this knot and it is also easy to tie correctly at home or in the field. Click on the photo below to expand.