^ Using public transit is great. For those coming from outside of DT proper, I think it's even better for doing sightseeing than driving (as long as you don't mind walking) since you don't have to constantly worry about where to park the car and how much it costs to do so.
I really enjoy walking all over downtown, personally. Especially since I can leave the car at home and not even worry about public transit. Walk out the front door and there I am!