Aside from a low clatter at startup, there are few initial signs that BMW's diesel-powered X5 is a different sort of beast. Drive it you must, though, because diesel power is addictive. As is the case with most diesels, the X5 xDrive35d loses some high-revving zing compared to its gas-powered siblings, but it gains enough thrust off the line to send the kids' iPods flying. The resulting mileage is equally impressive, even after you account for the higher cost of diesel.

Whether the X5 is worth considering in the luxury crossover category is open to question. Now in its third year, the current generation has a number of unaddressed shortcomings. As an upscale people-hauler, it works well enough. As a consummate luxury car costing $50,000, it falls a bit short. That said, if you're considering getting an X5, the diesel version is the one to look at — provided your local gas station sells diesel.

The X5 comes with three drivetrains, all labeled xDrive because they get standard all-wheel drive. (Click here to compare the 2009 and 2008 X5s.) Gas models include the six-cylinder xDrive30i and the V-8 xDrive48i. I tested the diesel six-cylinder xDrive35d that BMW added for 2009, but I've also driven the V-8.

• Diesel Power
• Ride & Handling
• Lingering Issues
• Crunching the Numbers
• X5 Diesel in the Market