I normally don't jump on my rant wagon (I'm sure admin will pull this thing) but here goes...
Fuel prices are not going to decrease. There's simply too much global demand and not enough production/reserves - even if we opened up the North Slope/Anwar/Gulf of Mexico and found a couple of as-of-yet undiscovered megafields. China alone has the potential to dwarf U.S. consumption in the next ten years, to say nothing of India.
When was the last time fuel prices "corrected" downward to any significant degree? I can remember .80c diesel and I'm sure many can remember it lower still - ever since, the price has creeped up - be it a war, hurricane, refinery explosion or whatever the excuse for prices going up they never come back down to what they were. I believe the majority of diesel consumption in the U.S. is on the commercial side and they are going to pass the cost along to the consumer...there is no incentive for the oil barons to lower the price on D.
The fundamental U.S. design is centered around the personal vehicle...for the most part there are few local schools, grocers, etc within walking distance...unless you live in a congested metropolital area. We bought the X because we need the passenger /carrying / towing capacity - if you need one you need one and the only solution I can see to $$$ is to brew your own bioD or buy less Chinese junk. Trading a paid off X for a rice burner will mean getting a pittance for your X and paying premium for the mpg...I'm not sure you wouldn't get more by parting one out in this economic climate.
My prediction: "Grab Iron" boys and girls cause we headed for a slide. How many folks are upside down right now on their 0% down over 60-72 mth gas guzzler? I look around my area and I can't believe everyone bought their Tahoes and Burbs etc for cash...they're everywhere...fuel budgets have doubled in the last 24 months, ARMs are coming due, and discretionary spending on our "service economy" is waaay down...unemployment is about to take a drastic jump. (I won't get into retirement losses or municipal government budget shortfalls due to fuel prices...that has its own special "rant"). One look at the interest manipulations since the FED started slicing the rates should be a wake up call. The FED is dropping and we're not seeing a concominant drop from the lenders (be it credit cards or mortgages) because they're recouping their speculative losses over the last year.
What really gets me riled is here in Texas contracts are going out to foreign companies to build highways and adding lanes instead of investment in comprehensive local/regional rail/bus/tram service and bike lanes

Government investment in transportation infrastructure keeps our tax dollars here at home, employing Americans, for the benefit of Americans.
The spousal unit has just pulled out her .45 so I'd better get off this thing...my apologies...
Cheers,
20f