I got the Lowepro DSLR Video Fastback 250AW, about $95 from B&H. It holds my 7D with a grip and either my 70-200L II or 100-400L attached to the camera, plus room in the lower storage compartment for 3 other lenses AND two speedlites. The upper compartment holds lots and lots of smaller stuff, and I can attach a tripod to the exterior straps. There's also an inner padded compartment for my laptop. Finally, the AW (all weather) option is an integrated waterproof cover that comes out from its attached self-contained pouch on the bottom to wrap around the entire backpack in case of inclement weather. It's easily carried onboard a plane, and I had no problem carrying it on my back all day for a trip with the family to Disney World. When carrying it on my back, I can quickly sling it around by slipping one arm out from the straps, bringing a zipper quick-release into view permitting very fast access to the camera when needed.