I've been in camera bag hell for most of my professional career. What does that mean? Essentially this- There is no such thing as the perfect camera bag. One has this, the other has that and some are just complete crap.
I used to like Kata's line of upper end bags (The inserts on their lower end bags compress to the thickness of paper) until three of their upper management team were being introduced to me by their importer's representative and while one of them pretended I wasn't even there, the other two looked at me like I was nothing but dirt. I informed them at that moment my only future interest in Kata was making sure everybody I knew in the photographic industry was how they truly felt about their customers. I dont care if Kata becomes the last manufacturer of camera bags in the world. If they do, I'll buy bubble wrap by the yard.
I also used to be quite enamored with LowePro but for the past few years it seems (In my opinion) that they stopped actually talking to photographers in order to get design input for their bags. I have a LowePro bag thats about 20 years old and I'll never get rid of it but none of their new products suit my needs.
How about Tamrac? They have two lines. One is their upper end, made here in the US and they're extremely durable. I like them and own a couple. Their other line (Made in China), which is much easier to find is great looking stuff and after about two years (Or less depending on use) the internal padding gets flattened out to the point that its like there is none at all. I cant recommend those for any use.
Tenba is one of my favorites. From the looks of things it appears that they actually include photographers in their design phase and as a result have some very cool and useful products. I'll be buying one of their "Shootout" backpacks in the next month or so. Their "Black Label" line of satchels and shoulder bags are very cool as well. I also own one of those. Their line is of great interest to me.
Another brand is Think Tank. I've never used them but from what I can see they look to be on the same level as Tenba, which in my opinion is damned good. They have some cool modular systems which are easily configured to an individual's needs.
So, I guess the next thing to cover is how does a person select the right one? First off- There is no such thing as the "perfect" camera bag, so stop looking for it. You stand a better chance of finding the mythological golden fleece. How do you determine what the best bag for you is? Obviously you start with how much gear you expect to be carrying? Does it need to adhere to the criteria set for flying on commercial airliners? There are many questions and as a result of needs, many of us end up with different kinds of bags for different situations. For example, when I'm just out and about I usually carry a minimal load out of one body, and usually three lenses such as my 105mm Macro, 24-70 and 70-200. Add in extra memory cards in their storage cases, a cleaning kit and a few other small accessories. That also allows me to use my smallest case which incidentially fits perfectly into the right pannier of my motorcycle.
For traveling by air, I usually have two bags to take on board because I never, ever check my camera gear. Ever. Did I mention that I never check my camera gear? (Damned good way to get it stolen/damaged) My two carry ons are a backpack for my camera gear and my laptop bag. I rarely carry them all together in one because frankly, it's just too damned heavy. My gear is heavy enough as it is.
So, there you have it- My view of camera bags. As I said- Each of us has their needs when it comes to them, singular or multiple and they may all be different. One last thing: When you decide its time to buy (another), take your gear with you to the store and actually try to fit everything in it.