In my bags, I try to use the right material for the right job. That means selecting something that’s tough enough, but not too heavy. Cotton canvas is out, as is leather; natural fibers rot if you expose them to moisture for too long; so if you’re in the tropics for 6 months, take something synthetic.
In a lot of the bags I make, I use the woven Dyneema melange. It’s incredibly strong, cut resistant, waterproof, and lighter than nylon of the same thickness. The sort of heather gray look is nice, as long as you give it some accents. I have in the past used Dyneema Composite, or DCF, but it has problems with pinholes forming after a while, and it looks like crap, and it’s really hard to sew, so I’ve mostly sworn off it.
I’ll also use a nylon canvas, similar to Cordura. All the neon highlights in the lineup on the home page are 1000d nylon canvas, with a waterproof coating (actually at present I don’t even have any uncoated fabrics in stock), as is any actual black fabric (the Businessman’s Lunch is a good example).
For linings, I’ve come to really like Gridstop, which is a brand of ripstop nylon, lightweight but reasonably tough. I also use a generous amount of hook and loop fastener, generic but strong, to hold the dividers. The foam padding is usually dense craft foam, although I’ve got some cork that I might experiment with, too.
All of the webbing I use is severe overkill in terms of strength, but I feel the wider shoulder straps help carrying the dense loads that land in camera bags. I use tex 75 (upholstery weight) nylon thread, and in critical areas (such as straps), kevlar thread of the same weight, which is twice as strong. Some of the hardware is custom, some off the shelf. The aluminum triglides I use were fabricated for me after I went through 3 or four different plastic ones and couldn’t find ones I liked.