Which engine should I get in this truck?

I'm thinking about buying a 2000-03 Ford Excursion 4X4. There are 3 engine options.

-Powerstroke 7.3L (Diesel)
-5.4L V8 (Gas)
-6.8L V10 (Gas)

Which one should I go for? I know I'm not going to get 45 mpg but, which one is the most fuel efficient?

Added (1). I KNOW I'M NOT GOING TO GET 45 MPG BUT, WHICH ONE IS THE MOST FUEL EFFICIENT?

Can you read this now?

Added (2). I'm guessing the 22MPG is highway mpg. What will it likely get in the city?

Added (3). Someone told me that in the winter the diesel has to be plugged in so the fuel doesn't gel.

The 7.3 will have the best MPG maybe 13 city and 18 highway.

The 7.3 will probably be the most fuel efficient and it should have more torque (incase if you ever want to tow) than the others and its reliability is well known to be great. You may get up to 22MPG with this engine.
5.4's arn't bad either if the spark plugs had been replaced since original plugs break off in the head, that should have been fixed by now it may get 16MPG (maybe)
the V10 I don't know much on but it will be the big gas user of the group.

If youre even thinking about fuel efficiency you don't want that truck, no youre not going to get 45mpg your going to get about 12. Maybe. And a huge tank that costs about 150$ to fill up. If your in the middle of your mid-life crisis get the V10…