My needs for carrying camera gear are often idiosyncratic. Normal people don't expect to use an RB67 and a Sunpak 622 in the field. I do, and I'd like to carry them on my bike too.
Yes, I did say on my bike. See, usually I just carry my G7 while I ride, because it fits nicely in any number of spots on my bike or person, doesn't weigh much, and takes decent pictures... especially if I take a panorama and stitch it, which I've gotten quite good at doing handheld. But I decided that the G7 wouldn't be enough for some dedicated exploration in Seattle some months ago...
One popular carrying style these days is what I'd like to term the "messenger/sling" style. In general, it tries to solve the problem with backpack-style carrying -- that just about every backpack requires you to take off your backpack and put it on the ground to get at the contents. A good bag of this style also is designed such that it lays against your back *just so* so it won't go flying around, unlike traditional shoulder bags.
Now, there's a good number of "sling" bags out there. I'd gone over the Internet and found a few that might fit the bill, based on some measurements with a ruler of my camera. On the other hand, once I started browsing the camera store, I discovered rapidly that most of them were the wrong shape to hold a desired "standard" load, consisting of one RB67 and one Sunpak 622. But then a helpful camera store employee told me that he knew exactly the right bag for me and spent a few minutes digging through the bags on display before he found the Ultra Pro 7.
I spent an hour or two walking around the store trying to figure out if it would work before I picked it up. Part of what makes this difficult is that I don't sit with my back at vertical while I bike. It's more like a 60 degree angle on my mountain bike and a 30 degree angle on my road bike.
But this bag can hold a 35mm camera with a lens mounted, two extra lenses, and an RB67 with back and lens all mounted. Plus room for accessories. The RB67 is a little tight in and out, but the 35mm isn't. Or I can carry the RB67 with a Sunpak 622. Or I can carry the 35mm camera, a lens, a Vivitar 285HV, and a Sunpak 622.
Tamrac has their attachment system for accessories. This means that you've got a loop on the strap for an "SAS" item like a memory card holder, plus two loops on the side for "MAS" items like a lens holder. These systems are somewhat negotiable, so I ended up putting my Lowepro pocket for my G7 around the strap on one end and a Domke flash pocket on the other, which puts everything at ready access. I also got their MAS filter pocket for filters.
Like I said, I got it for a trip to Seattle. I shipped my mountain bike beforehand on Amtrak so I could ride instead of drive. The ultimate test was a 20 mile ride around town, stopping at lights and photo points, and shooting. This included a climb up a 9% grade. It passed the test. I also took it hiking a bunch of times and on some outdoor model shoots.
The sad part of the story is, of course, that you will always end up having twenty million different camera bags for different situations. It's inevitable. It's just a matter of trying to reduce that down to a few optimum options, I think.
My next problem is figuring out what to do for household photo gear storage. See, I used to just store everything in the camera bag... but now I'm wanting to store everything in ?something? and then grab whatever I want to take out shooting and put it in a bag. Not sure what to do about that, but I don't want to spend a bunch of money trying out options that don't work.