Drop bars adjusted to be about saddle height on the flats with an inline brake lever for the front brake is the most ideal bar I can think of for long distance commuting. You get 3 viable positions which you have hands ready on the brakes, 2 positions which you can shift gears and a bunch of positions in between. You can ride on the flat tops of the bar for city situations, on top of the shifters for a slightly more aggressive position and then in the drops for windy days/descending/an even more aggressive position.

It's all personal preference but I don't see the point in flat bars. I fail to see how they offer "better control" or "better visibility" than the many other bars available. H-Bars, drop bars, bullhorns, riser bars, moustache bars or albatross bars are all better suited to commuting. Flat bars are the most limited and uncomfortable bars you could possibly pick...