Camera bags are a very personal thing! What works for one photographer may not for the next. Messenger style bags work well for me, when I am travelling or getting around with my gear on the motorbike. There are several things that are important to me with my choice of camera bags.
1. Quality (Why pay all that money for something that falls apart at the worst moment)
2. Discreteness (I don't want to stand out as carrying lots of expensive gear!)
3. Functionality (It has to work as designed!)
So my bag for the last twelve months or so has been the Retrospective 7 by Think Tank
The think Tank checks all these for me. I recently went to Europe and this bag was abused and used! I routinely was carrying FAR more than it was ever designed to and held up beautifully! I especially like the low key look of these bags and that they are not splattered with logos and clues as to their contents. Very handy as I do a lot of night shooting in the wee hours. I appreciated the fact I didn't look like a big target for thieves.
The quality and robustness of these bags has impressed me no end! I am actually going to buy another one to use as my bag when I am riding my motorcycle! No doubt it will see double duty as a camera bag as well, but these bags are just so impressive not to use all the time!
The layout and customisation is also very handy as I can lay out the bag depending on what I need for any particular job. I will let you head over to their website to see for yourself, but from me...Two big thumbs up!