Even if you are gentle on acceleration/deceleration, things like hills and stoplights/signs can really knock your mileage down on a heavy vehicle like this. Same goes for speeds over the 70-75 MPH range. I think that's one reason that some people really can achieve 24-25 MPG (real, not trip computer) on the highway.
I read today in Reuters that AAA now calculates the national average for a gallon of regular to have gone back above $2/gallon. I can believe it, as I just paid $2.35/gallon yesterday for Chevron premium.
Gas mileage was a minor consideration in my decision to buy a V6, since it was only a 10% improvement over the V8. But I was keeping in mind the actual cost of gas, adjusted (approximately) for inflation. Here are some recent figures (in today's prices) for an average of all fuel grades:
1964: $1.83
1974: $1.99
1981: $2.83
1990: $1.61
2000: $1.61
2004: $2.04 (prob. early January)
So we aren't paying as much in real terms as we were in the early '80s, even with the price rise in the past couple of months--maybe it's $2.25 now.
But recall the vehicle situation in the early '80s. A used Nissan 310 might sell for as much as a used Cadillac, and would sell much more easily. Toyota's main engine for things like the pickups (and quite a few cars) was the 2.4L 22R, and a 2WD pickup probably got 27MPG on the highway. My Celica with the 22R would get over 30 MPG on the highway.
If we see $3/gallon gas, some of the big pickups and SUVs will see $100 fill-ups. We might indeed see some significant effects on new vehicle sales. And if gas lines return, we'll see even bigger ones, though I don't think lines are very likely.
As for synthetic oil, my previous experience was that it was a significant help if you drive much in cold temps and change the fluid in your diffs and transfer case. Maybe not much help if used in the engine, though.
Finally, (sorry about the overlong post) I run 36 PSI in my (OEM Bridgestone) tires and like it as a compromise. Ride is not harsh, and it improves MPG and handling a little. I suspect it improves wear slightly, but I don't care about that.