Just a thought, if you don't have any preconceived preferences, the best choice to start out with will probably be the type of bike intended for your primary use, a commuter or urban bike.
Any type of bike can be used for commuting, your needs and environment will determine which is best. Your desire to ride fast, tour, hit the trails, or whatever can change the equation yet again, but that takes time to decide....or you may never decide and end up with more than one bike.