Upload & Sell: Off
I have Thinktank Retrospective in 3 sizes; Crumpler in 3 sizes, one Billingham, one Domke, one Lowepro and Timbuk2 in two sizses. It's nice to have a choice and use the bag that best fits the amount of gear you're carrying and your style mood.
The Retrospective and Crumpler designs are the easiest to work out of and are great for travel due to the many pockets and comfy straps/shoulder pads. The Domke is rustic and cool but not nearly as practical, suffering a serious lack of pockets and shoulder pad. The Billingham is beautiful, ultra soft inside but an otherwise rather spartan design like the Domke. The Timbuk2 sucks with their insert but is great with a Crumpler Haven insert. I actually carry the Timbuk2 the most since it goes with me to work and contains both my lunch and camera. Plus the cross strap keeps it from falling off when you run or bike.