I thought I'd mention something different altogether and that is Courierware, handmade in Vermont by local labor. The owner is Eric Turan and he was the original designer of the modern messenger style bag as we now know it (he started making them 27 years ago in Cambridge MA when he owned a bicycle messenger service.)
He's also the maker of the "Bare Bones Bag" that is being sold by Stephen Schaub (
http://www.indianhillimageworks.com/catalog/camera-bags/the-bare-bones-bag-evolution-bbb-e)
I've had Eric make me several bags and he will do custom requests (different pockets, materials, etc..) What I really like about these bags is not only their build quality and their lifetime warranty, but the fact that they are very subtle and don't attract any attention. I like Billingham but personally feel that they are too 'frilly' and fancy looking. Also every thief knows that a ThinkTank (made in China) holds camera gear. These bags don't shout out anything and yet are super well made and function perfectly (easy access to everything yet well protected.) They don't even have an outside label (Eric's website shows older images with the label on the outside, but there is now just one small label on the inside.) His website is kind of rudimentary and not that great, but if you talk to him in person he will be more than accommodating and build to your own specs (
http://www.courierwareusa.com/index.php?option=com_content&view=article&id=39&Itemid=162 ) The website doesn't really emphasize how well made these bags are, unfortunately (another good thing is that they are not overly expensive, either.)
I have several of them including two "mini" sizes which work great with a Leica (or two) and a couple of lenses. I also have an 'extra small' and a 'small' for other cameras (extra small for Nikon F3 and lenses, and small for DSLR and lenses.)
Here's a video of one of them in action. The great thing is that they 'disappear' on your body (hug your body) and are extremely comfortable.
http://www.youtube.com/watch?v=ps4HWNC9GDE
I have no monetary or personal connection with Eric and Courierware. I just really like the bags and they work very well for me. Several photographers I know also use them and feel the same way.