I have owned a lot of bags over the years. Some good some not good at all. Think tank makes great card wallets (I own a few) I would guess that same though and construction hold to their bags as well. Domke makes one seriously good 'shooters' bag easy to get gear in and out one handed and just the right shapes. They hold up very well to abuse and wear. the downside, they are easy to get in to... they do not offer much theft security. Great bags to shoot out of not great to carry long distances. (I own 4 of them, one is 18 years old and heavily used every few days)
Crumpler makes the toughest bags I have ever owned. They are seriously tough. There are a huge array of styles and types. The 'bucket' idea is great buy a bag (any bag) and drop the padded camera 'bucket' into it. Most of the bags they make also do not scream camera bag. I own the biggest back pack bag to a tiny slip cover bag and a few in between. The backpack has been on 4 contents and I have no idea how many countries for many years. It still looks like I bought it yesterday.
I also own a billingham it is maybe a bit better looking than the Domke and perhaps slightly more functional but the price tag is so much more that I would recommend a domke over it 100% unless you have loads of cash and the look of the bag matters a lot.
A ok site for looking at bags it has user submitted photos of the bag and gear packed in it. It gives a fairly good idea of how much it carries.
http://www.cambags.com/bag-type/shoulder-bags-menu.html