Crumpler's Karachi Outpost

The Karachi Outpost from Crumpler looks just as casual and cool as the other products they offer, but it stores more. Take your tripod, 11-inch MacBook Air, lenses, and, of course, cameras, and you'll still have room leftover for odds and ends. A separate cover stored efficiently in a zipped compartment near the top will save you if and when you're stuck with all your gear in a torrential downpour or just want things to be extra secured. 
[$265; crumpler.com]