I ran across a couple of interesting information resources recently, and thought them worth sharing.
FuelEconomy.gov is an EPA website providing automobile mileage information. The hybrid vehicle information isn't quite up to what you'll find at Green Car Congress or HybridCars.com, and you're better off seeking alternative fuel info at Alternative Energy Blog, but what FuelEconomy.gov does have going for it is the complete EPA database of vehicle mileage ratings, EPA air pollution and greenhouse gas emissions ratings, and NHTSA crash test data. This allows it to produces tables showing the most and least fuel-efficient cars (Honda Insight manual, most -- 60 city/66 hwy; Lambourghini L-147 Murcielago, least -- 9/13) and trucks/SUVs (Toyota Rav4 manual, most -- 24/30; Ford F150 and Land Rover Discovery & Range Rovers, tied for least -- 12/16). Sadly, the NaviStar CXT (see image above) is not yet listed, as it would show the worst mileage of all (6/10).
The other resource is even more extensive.
The Energy Information Administration at the the US Department of Energy has an astounding amount of data on a variety of energy-related subjects. You want residential consumption data for natural gas? They have it (PDF). You want the total renewable net Kilowatthours generation, by state and technology? They have it. You want world petroleum consumption since 1960 for major OECD and non-OECD countries? They have it. And so forth. The main downside is that much of the information is a few years old (the natural gas listings are from 2001, the renewable data are from 2000, and the world consumption listing goes through 2002), although it's possible to dig up more recent datasets, such as this listing of Top World Oil Consumers and Importers, by million barrels/day, from 2003.