Watch the video, and you’ll see, but I was able to get:
17″ HP EliteBook laptop, 15″ HP G62 laptop, Canon EOS30D camera body, Canon 50mm lens, Canon 70-300mm zoom lens, Canon 430EX Speedlite Flash, Sony PSP, Nintendo DS, Canon VIXIA video camera, Kodak ZI-8 video camera, a legal pad of paper, the power bricks for every device I just listed, a Canon battery charger with an extra battery, two cleaning cloth kits, a full Sunpak tripod, a pair of Sony noise-cancelling headphones, a Razer DeathAdder mouse, a Logitech wireless laptop mouse, a stack of my business cards, three ink pens, and my car keys.
I could have fit more small stuff in there, believe me. This thing is massive. Yes, it costs a bit of money, but the durability, strength, and clever use of space to maximize storage is worth every penny.
The only downside I can see is the lack of a waist strap. Not really a big deal, but there it is.