When I bought my Tundra, I had two goals in mind. I wanted something that would fit both my four wheeler and a small dirtbike that I had at the time. I also wanted something that would drive like a tank through the most apocalyptic Nor'Easters. The ground clearance alone does the trick more often than not, but the 4X4 gets me up the snow covered mountain trail which is my in-law's driveway.
Ideally, I will only use the truck on an as-needed basis and have a separate economy car for daily driving. I recently traded my motorcycle for a 1991 Civic. Unfortunately I'll still be driving the truck until I can afford to get the Civic road worthy (needs wheel bearings and tires).
I just popped the ecomod cherry by adding a Scan Gauge! Otherwise, the truck looks pretty stock other than having the mirrors folded back. The driver has been modded and I'm getting some really great economy that way. I've been driving a lot slower, seeking more efficient routes and my diet helped me shed about 20lbs from the loaded vehicle weight.
Even with the Honda, I'll want to continue to mod out the truck. I'm looking into various aero mods. I'd like to fabricate some sort of fastback cap to reduce air separation. I also want to clean up the undercarriage and perhaps the grill area. I'm looking for an electric radiator fan that I can replace the mechanical one with.