The 2008 Impala stays largely unchanged from 2007, adding satellite radio as standard on all models, and defines "plain vanilla" among full-sized, front-wheel-drive sedans. A touch of "green" sprouts in the 3.9-liter V6, standard on the LTZ line, which is E85 ethanol-gasoline compatible. But vanilla sells. Chevy sold 290,000 Impalas in 2006, ranking it the seventh best selling vehicle in the U.S.

The Impala line, which originated in 1958, has a performance heritage that still finds expression in the Impala SS trim, which fields a 303-hp, 5.3-liter V8. The new green streak appears even in this performance line, via GM's Active Fuel Management technology, which shuts down half the cylinders during highway cruising to boost fuel economy. Yet the SS still performs well, drilling the 0-60-mph run in 6.4 seconds. Most of those impressive sales figures, however, represent one of the lesser engine choices, with the V6 engines offering up to 28 mpg highway, according to the EPA.

The base LS model rolls on 16-inch wheels, with front bench seating, full power accessories, a power driver seat, tilt steering wheel, keyless entry, and a CD audio system with MP3 jack. A functional but plain interior suits the overall presentation of the Impala. The automotive press finds that the Hyundai Azera represents a better mix of luxury and value, the Toyota Avalon has more refinement, and the Chrysler 300 offers more agility and style. Yet none of them matches the sales figures of the Impala.

So why is the Impala so popular? As an inexpensive, economical people mover, it can seat six adults - try that in any of the aforementioned competitors. The Impala also does well in crash testing. The LTZ and SS lines include standard antilock brakes and traction control, which are optional on other trims. Standard on all Impalas are full-length side curtain airbags, tire pressure monitors, and an OnStar system. 2LT, LTZ, and SS trims feature standard stability control.

While the SS understandably stands out in handling, the rest of the line, when equipped with the stock soft front-wheel-drive suspension, does not. Overall, the standard Impala represents a competent highway cruiser that comfortably and efficiently hauls six adults.