Now on to the big bag. The definitely not the lightweight bag. My new favorite big bag is the Airport Security from Think Tank Photo. It is large enough to fit two large bodies, two flashes, and lenses covering 14mm to 600mm with room for teleconverters, filters, remotes, cables, diffusers, the lot. The added advantage to this bag is that is has wheels! I can tote it around airports, to and from cars without breaking my back. These wheels are great for smooth surfaces but not so good for rough terrain. When I do need to carry a lot of gear over rough ground I resort to my old faithful Lowepro Pro Trekker. For the majority of the time I work from near enough to my car to leave the bag behind with a long tripod mounted lens (200-400 or 600mm) on my shoulder, a second camera body with a tele- zoom (70-200 or 24-70) round my neck and a wide zoom (14-24 or 24-70 depending on the circumstances) in my pocket or bumbag.
You can see here the Airport Security's main compartment with the majority of the gear. The bag is so deep that you can easily store equipment stacked together with padding in between.
Inside the lid there are four see through pockets for storing accessories like filters and cables. There are two more pockets on the outside where I place AA batteries, CF cards, note books, pens, passport and an external hard drive for backing up the laptop. All of this fits neatly in this non assuming black bag that doesn't scream out 'expensive camera equipment inside'. Which is great for drawing attention from theives and airport attendants. And did I mention I don't have to pick it up, it has wheels!