1: The one you will ride.
2: The one that fits.
3: Sounds like you are looking at a hybrid. Wider tires and fenders to get you around town. With a little work on the engine and a pair of slick tires, you will be plenty fast.
4: Cyclocross bikes are another alternative. Usually more race oriented than your standard hybrid, but beefier than a road bike.

Whatever you buy, go thru a bike fitting. You will be amazed at how much difference it will make in your comfort and efficiency.