I guess my recommendation would be to go to bikeradar, for example, and check out the pro bikes.
Not because they do it right, but because you''ll see that they are all very different and there are various personal preferences at play. I know Jens Voigt has a set-up that would get quite a bit of bashing on a certain German forum, while I remember Gustav Larsson being what you'd might consider mainstream right now. I believe Spartacus is somewhere right in between, but I could be wrong. None of those is better than another, just different.
Voigt and Sastre get a more upright climbing position, which might be good for them but not somebody else.
For most bikes you'd start putting your hoods where you like them to be, and then figure out how much lower you want to be in the drops and how much higher on top of the bar.
It gets complicated once you factor in all the variables, reach and drop of the stem, reach and drop of the handlebar, length and shape of your hoods and levers, some might say thickness of your bartape and gloves should be in there, too. I'd suggest not sweating a couple of mms either way, but you can get more than a cm difference, easily, and that's something to pay attention to.
It's all pretty simple geometry and you just calculate your way back from the hoods to the steerer.
So, if you are not sure what shape bars you like, I'd probably go for pretty much the cheapest you can find and just see how you like it.
"Nothing compares to the simple pleasures of a bike ride," said John F. Kennedy, a man who had the pleasure of Marilyn Monroe.