I have multiple bags:
- An old, well made but very worn Galen Rowell shoulder bag that carries about everything.
- A small Tamarac shoulder bag that carries a smaller kit, on body (50D), two lenses, a flash and few essentials. It can also be worn as a sling which is how I usually use it.
- A Fuji vest (free for buying lots of Velvia) that is my preferred method for hiking. I carry one camera and lens mounted on a tripod or on a strap, a couple of extra lenses, 3 filters and a flash. That's about it. And I'm not burdened with any extra equipment.
- A tool belt that gets used as a tripod apron is static situations.
- And a small Canon backpack that I just picked up for about $70. It holds both bodies, 4 lenses, two flashes, remotes, batteries, filters, cords, manuals, chargers, tools, and almost anything else. It also has tripod loops (both along the bottom and either side). But it doesn't hold a laptop or any non photo related gear.
I really wanted a backpack that would hold everything plus a laptop. There is an Ape Case (model 4000 something) that will do just that and has removable wheels to boot. It is about $150. But the Canon bag holds almost as much (except the laptop) for much less and is a smaller bag. I don't plan on working out of the full backpack often. I'll use it to get everything on site then use lighter methods to carry the gear I'm working with.
Consider having various bags for various situations. Consider if you really need to carry the laptop and extra clothing with the camera gear. Really evaluate how you want to use the bag. Maybe a smaller backpack and standard carry on suitcase would serve you as well. But, above all, don't expect to find the "perfect bag". It ain't being made!!

