The 2010 X5, which is called a "sports activity vehicle" by BMW, combines some of the best attributes of a sport wagon and an SUV, offering better handling than most SUVs yet some measure of off-road ability and toughness. In the first and second rows, the X5 offers a good, quiet ride as well. As in BMW's sedans, there's also plenty of opportunity to upgrade the X5 with high-tech options. An optional diesel engine provides impressive power yet delivers surprising fuel economy, and an all-new M version turns the X5 into a seriously impressive performer.