I would go for a Billingham, I know that they are expensive, but they are well made, and can last a lifetime (literally). If that is the style you want there really isn't any other substitute especially if you amortise the costs of the lifetime of the bag.
My choice would be a Hadley Pro 2020, with the additional shoulder pad - these are comfortable to wear (the shoulder pad makes a difference on a long day) and can be worn as a shoulder or a crossover bag, the handle is also useful (the strap can be folded in the top of the bag). Hard wearing and from a conversation with Billingham, Fibrenyte is more hardwearing than the traditional canvas. They are also very waterproof, I have roadtested this bit!
If you wait for sales they are often discounted (up to 20%).
I often use mine for one camera c/w lens, an extra lens, battery, etc, and there is still plenty of room for a bottle of water, glasses case, notebook, etc. Magazines, guides etc can easily be slipped between the insert and the bag side.
My first one (10 years old) has had an immense amount of use (equates to 33p a week to date!!), and is looking tired, with a some wear showing on one of the panels. Billingham offer a repair service and quoted me £37 to repair including shipping but I opted to treat myself to a new version in the last Black Friday Sales (20% off). Beacuse the inserts are the same, I can easily swap between bags and I will still use old one if I'm going to unsavoury locations, it won't stand out!
Quite a choice of colours from the traditional photographers tan to the more urban friendly black or sage green.
BTW Wex have a Billingham Promotion at the moment 10% - use coupon BILL-10 at checkout