We use
The Parking Spot whenever we drive to the airport... we prefer the south location on Valley View. If you click through the link above, select which location is closest for you and make sure to print the coupon as it is a great savings!
You can choose from covered or open-air parking, both at what I would consider reasonable rates for the pick-up/drop-off service. They will come to your car to pick you and your luggage off, assist with your luggage and drop you at the terminal. When you arrive back at DFW, you will be driven directly to your car (don't lose the card where they write your parking location!), unlike the onsite DFW parking where you schlep your luggage throughout the parking lot!
Hope this helps!