Here are a couple of pictures.
 

I also replaced all of the exterior bulbs with LED lights yesterday.

That's a nice looking truck!

I bought a 2000 Excursion with a 7.3L in November 2014. It was my first diesel truck too. I picked it up in Texas and drove it back to California. I didn't even make it home before the water pump went so my first experience was putting a new one on.

In fact, if yours hasn't been changed, be on the lookout as they usually last around 150k. You can see how yours is doing by grabbing the top of the fan and trying to move it from front to back. If you get a lot of play, it's about ready to start leaking, and I would change it out as a preventative measure. If it leaks while you're driving, you may or may not catch it before the engine overheats.

There are a number of suggested fixes on these trucks. The stock fuel pickup system isn't very good and introduces a lot of air into the fuel, which isn't good for the injectors, for example. Search for hutch mod and harpoon mod, these are the most common fuel system upgrades. I went with an aftermarket kit that included everything.

Also, if you plan on doing any heavy towing, you're going to want to upgrade the transmission cooler to a 6.0 cooler. It's much larger than the 7.3 cooler and your transmission will thank you for it.

If your headlights are like mine were (and they look like it), they're awful at night. I could have seen more with a maglight and a patch over one eye than I could with the yellowed, faded stock headlights on high beams at night. There are a few options. Some upgrade the whole frontend with an 05+ grill, header panel, and headlights. I ended up going the cheaper route and getting a pair of aftermarket headlights and modifying the existing header panel myself. It greatly improved both the look of the truck and my visibility at night.

I'm getting ready now to pull the trigger on $1500 worth of upgrades/fixes to mine now.

After 25 posts you can add a signature,...
which for most of us is information about your truck so we don't keep asking you to repeat constantly.
Look at the door pillar. What is the build date of yours?

The truck came from Texas and is rust free. The build date is 01/01.

See if your HPO lines are still stainless braided. If they are get a new set from Clay asap!
There's nothing worse than something as stupid as those leaving you on the side of the road! Not to mention the mess it makes.... ask me how I know

Early 2001 4R100 transmissions like yours had something called a mechanical diode. They broke with regularity. Good news is you have a rebuilt tranny, and that part should never be in a rebuilt tranny. Should. What can you tell us about who did the rebuild? Any parts listed?

Nice looking truck! We crew cab shortys rule. :)

Another option to clean up your headlights is 100% DEET, the bug repellent. Apply with a sock and it will polish up pretty good. Doesn't last forever but hey cheap and easy.

A good read is the Failure Prevention thread. As mentioned above the learning curve can be steep, and nobody knows it all, so be free with the questions.

And here's your handy Explorers Map of 7.3ville.

Very nice looking truck.