"What's the best bike?" A fair question, but one not readily answered. Where are you going? Across town or across the country? What route will you take? City street, paved path, or forest trail? Do you plan to carry anything with you, or just the clothes on your back?
Don't overlook the most important question: Why? Why do you choose to ride? Ethos or eco? Do you ride to save the planet, or to save yourself? Once you know your own heart, the bike will reveal itself to you.