I have never had that issue with people stealing my camelbak. If it isn't on my back then it is being used as a pillow when I take a nap inbetween shows.
I agree. I've taken the same one with me the past four years and I don't know anyone who has had one stolen (we had some smokes and a bottle of Crown Royal stolen once, but leaving those out is asking for it). And they come in all sizes, so you need not buy a tiny one if you want to haul your shit around with you. Or you can just get a bladder and hose and add them to your backpack of choice.
I hate to recommend Walmart for anything, but I was in no hurry the last time I was there and got to wandering, and noticed that they had a pretty nice looking Coleman and one that was presumably a house brand. I think they were both around $40 and were a mediumish size, with multiple pockets, chest straps, comfy looking backs, and space for whatever you need, but not huge. I'll probably keep using my 7-8 year-old High Sierra, but finding myself with a little extra cash might convince me to buy a new pack this year. I wish I had pulled the trigger on one of the Ultimate Direction packs that somebody here pointed out on Woot, they were a steal.