Since I spend the majority of time on the drops, I set the angle of the final straight section of the drops for maximum comfort. Like others have indicated, I position the brake levers for accessibility from both the hoods and the drops. The top of my stem is typically about 4" below the top of my saddle.

Anyone who doesn't position their bars exactly the same as mine is obviously deformed! j/k
Seriously, looking at other peoples setups, aesthetically I think as long as the initial forward throw of the bars is horizontal or downward, and the final straight (rearward) part of the drops is also horizontal or or downward, my sense of aesthetics is not violated. The brake levers can anywhere that puts them roughly parallel to the curved section of the drops.