In my case a lot of it depends on the shape of the bar (anatomic or not), whether the bike has brifters or not and whether I have a clip on aerobar.

In most cases, the bars are position in the way noglider describes, with the levers just at the curvature on the bar (levers pointing down) like this:



When an aerobar is involed, is a different story: I ride in the drops only to get a different hand position and I need equal opportunity access to the brakes from all other three positions, so the result is something like this: