GrIDsure seems like an interesting option. It won't work for everybody though. I've been watching the demos and I can't remember the patterns I see - as soon as there are numbers in there my pattern memory disappears. This is presumably because it's easy for me to remember numbers. The longer the PIN, the better. So, I would have to walk around with a note of my pattern.. not good! But I'm sure it'll work better for most other people than standard PIN codes.