i set my bikes with a compromise between having: 1) the flat bottom part of the bar level (more or less parallel with non-sloping top tube); 2) brake levers vertical to the ground; and 3) brake hoods flat with top part of bar
to me it strikes a nice balance between aesthetics and utility. i use the flats often and they are most comfy when level. vertical levers allows me to grab them from the hoods or the drops. and flat hood<->bar interface makes riding the hoods easier (big fan of new campy hoods)
of course i only have a cyclo-x lever now so this is now inapplicable
i think the examples with the canted deep drop bars are for merely for show. most of them have wraps only on the upper part of the bar... i dont think anyone with normal vertebrae column can ride the drops with such setup