A long trip is more up to your legs than to the bike. I see bikes with flat bars used on 50 mile and 100 mile charity rides all of the time. But, most people would benefit from being able to move their hands and back to a variety of positions on a long ride. Over a two or three hour period, using drop bars, and moving your hands from near the stem, out to the brake hoods, and down to the drops helps prevent fatique, soreness, and cramps.

But, for an hour's ride, such as commuting to work, a flat bar works well, especially when it enables a rider to have a "head's up" postion and keep a closer eye on the truck on his right, and the SUV on his left.