If you sign up for Fastbreak, you can skip the counter altogether and just go right to the car lot. After you pick up luggage, go down one level. Budget is across the street and up one floor (there is an elevator). We like Budget because of this feature (especially nice when there are long lines at the counter!) and because they do not charge for allowing a spouse to also drive the vehicle.
Note: If you sign up for Fastbreak after you have already made your reservation, you will need to call Budget after your Fastbreak card arrives in the mail (I think our card took about 3 weeks to arrive). Budget can then code your reservation as Fastbreak.