If you're searching for that one perfect bag, give up now. There are excellent bags, but each has a purpose and eventually you'll end up with a closet full of them. I have 5 or 6 that I've narrowed it down to, and each has their place and time.
Storage:
I store my shooting gear in a TT Airport Acceleration backpack. All my lenses, bodies, flashes, PWs and other shooting-related accessories manage to fit inside. It weighs a good 50 pounds, but then I rarely take the whole thing along.
My chargers and cables sit on a shelf in the storage closet. They get tossed into a Domke J-2 for transportation.
Computer equipment including card readers, hard drives, backup drives, etc. live on another shelf. These come along in a TT Urban Disguise 50, which also fits a 15" MacBook Pro.
Tripods, monopods, lightstands, etc. I store in TT Humongous Bazooka. Also used to transport the stuff.
I have a whole shelf in my closet to store the rest of my bags - a mix of Think Tank & Domke stuff.
Travel & Transportation:
I choose which bag to take depending on what I'll be doing. If I'm going by car, I have a ton of space so I generally end up taking way more than I need. But it's nice to have choice.
For flight travel, it really depends on the gig. For weddings, I more often than not end up packing along almost everything. All 50 pounds of backpack comes along as carry-on with another 20lbs or so in the Urban Disguise comprising my laptop, portable hard drives (3), readers, misc. cables and all documents I might need.
The Bazooka gets tossed into a duffle bag, along with the Domke containing all my chargers. Somehow, I always end up with another bag of miscellaneous accessories - tape, reflectors, umbrellas (the rain kind), tarps, etc. You just never know what you'll need!
For other gigs - events and travel - I don't need as much stuff and usually know ahead of time exactly what I'll need. So I pare down as much as possible while still having everything backed up and pack it into the smallest bag I can manage.
Usage:
Again, totally dependent on the job at hand. I usually work with a camera on each shoulder so I prefer to have a beltpack. Taking out two bodies, two lenses and two strobes also frees up a lot of space in the backpack, so taking that along would be overkill. If possible, I'll bring only the bare minimum and stash backup gear in a hotel room.
Advice:
Try to figure out what you think you'll need for any specific shoot, and take just that. Don't worry about accumulating a lot of bags - once you have a few to pick from, you'll naturally gravitate towards your favorites. Keep those, sell the others.
One other fun thing to do might be to take along just a couple of lenses in a smaller bag and forcing yourself to use just those. I recently brought only a 17-40 and 300 2.8 to a model shoot and never missed the in-between focal lengths. And this way, you learn to work with what you've got.
