Using Tiffany Town Car, the drive was approximately 20-30 minutes. Our driver, Inez, was great - pointing out landmarks (ie. The top of ToT) and filling us in on some tips. Have a great time!
With Disney's Magical Express (DME), you might be on your way while others on your flight are still waiting for their luggage -- or you might just miss a DME coach, and you'll have to wait for the next coach that goes to your resort.
Each DME coach will make 3 or 4 stops. You could be the first stop. You could be the last stop. The stops should be fairly brief because the luggage will be on luggage trucks, not in the belly of your coach. But each stop will add time.
So there's no easy answer. I would assume about an hour from the time you arrive at the Disney Welcome Center at Orlando Airport to a WDW hotel. But sometimes it will take less, and sometimes more time.