Features I must have in a backpack: waist straps, waterproof bottom, top handle, and short enough for short me when strapped and loaded.

Feature I desperately want: backpack with a detachable purse/waistpack instead of a top pocket, so that I can take my essential stuff without taking everything, or taking time to transfer many small objects.

Feature I'd pay extra for: backpack with all of the above that is aesthetically pleasing enough for a professional designer to wear to work, including meetings.