I do the same as Ziemas. I padlock a grocery pannier to my rack but I also have the Arkel Bug backpack/pannier. The main thing that I have changed is just the way I look at my travel. If you think like you are driving a car then you won't get the full benefits of biking and it could bother you. You have to think like you're riding a bike. I just keep my lock, a coffee mug, a bungie net, and multitool in the bag I keep on my bike. My bike light and anything else that is worth much I keep in my backpack. Most people around where I live don't think that a bike could have anything worth stealing and if they know that bikes are expensive they are probably riders themselves and won't steal stuff. Last week even I forgot to lock my bike up on campus for 4 hours and it was still there when I got back. And it was right in the middle of campus in front of the library. Just think like a cyclist and you'll do fine and have a lot more fun.