Like Chris said, no reason not make the officer's job a little easier. I do this by getting out of the car when pulled over. I mean, anything could happen when he walks up behind an unknown person. By being outside the car he knows what he's dealing with, so I'm removing some of that uncertainty. Then I move quickly towards his car. He's a busy guy. I don't want to wast his time. If I'm carrying, I'm always sure to lift my shirt up to show him where it is. I don't want the officer to get any surprises later. If for some reason it's not safe to get out of the car to help him out, then I wait in my car with the lights off. I don't want to hurt his keen low-light vision with my stupid dome light. When he asks for my DL and registration, I lunge for the glovebox to get it. Again, he's a busy guy so I don't want to waste his time.
Seriously though....what Chris said. It costs you nothing, speeds up the process, and makes their hard job a little easier. That can be the difference between getting a warning and getting a ticket.