I've tried to think of what the ultimate vehicle would be, and here's what I've come up with:
It would of course fly, silently of course, it would have one or two seats, like a fighter cockpit, it would be very small so it could fly in tight spaces, it would be capable of virtually any speed, it would have voice command and autopilot that would keep it from hitting anything, you could tell it to fly in a formation with anything and it would hold it's relative position without hitting anything, it could go into stealth mode where no one else could see you, you could listen to anything happening outside of the craft, and last but not least, you could time travel with it. You could travel to any point in time, and observe anything that happened in the past without being observed, and learn the truth about anything in yours' or man's history that you ever wondered about.
How much would you pay to rent the ultimate vehicle for a day?
Now suppose your memory and any photos or recordings of anything you observed while in this vehicle would be erased upon return - you could observe anything in history and know the truth while observing it, but once back, you'd have zero recollection of anything you saw earlier while in the ultimate vehicle, it would be like you never took the vehicle out. How much would you pay to rent the vehicle for a day?
To me its kind of a fun question, it gets to why you'd want knowledge.