I rode a drop-bar bike to commute (18-mile round trip, about 1/3 in city traffic) for the first five years of my final job before retirement. Then a flat-bar hybrid with time-trial-style aero bars for the last 15 years.

Once I'd switched, I (mildly) regretted the years commuting on the drop-bar bike. The flat bars felt much safer in traffic, and the aero bars boosted my speed everywhere else. Now that I'm retired, my 12 to 15 hours per week of riding consist of about 50% hybrid, 45% fixed-gear bike with bullhorn bars, and 5% drop bars, all with added aero bars.