How far and what sort of terrain and traffic?

I rode my buddies drop (older Cannondale of some sort) bar bike for a week and just couldn't get used to it. It was fine and sometimes better on more open roads but I didn't like it in town mixed with traffic (just my experience). For traffic, I really like my flat bar best because of brake and shifter locations. I would recommend some bar ends should you go this route, extra hand positions are good and I have to agree that a straight flat bar is not the most natural position for longer rides. I tried a few sets of bar ends before deciding on these for mine

http://ritcheylogic.com/web/Ritchey%...7927&live=true

The bend and angle inward really seems to fit my natural hand/arm positions and end up giving me another position choice (half bar end/half flat bar). Didn't like the straight bar ends nearly as much. Stick your arms out at a 45 deg. angle and you may see your hands naturally going to a near 45 deg too (if that makes sense). Other people and bike/handlebar set-ups may be different.