Bike for metro suburb commuting?
I live 16 miles from work and enjoy biking to and fro, mostly surface streets and sidewalks; it's a pretty decent workout. The bike I have, however, is over 15 years old and is a heavy mountain bike (Diamondback). I'm in the market for a new bike but there are so many different kinds now! Any suggestions for a bike that can handle road commuting and fine gravel path? I'm not looking to conquer insanely rocky/mountainous terrain.