Back in 1997, a revamped Century hit the showrooms with a bigger, more ergonomic interior and roomier trunk, all wrapped in smooth, flowing sheet metal that Buick stylists hoped would have a long shelf life. It appears they got their wish. Now into its sixth year of production, the popularity of today's Century proves we shouldn't underestimate the market power of America's senior citizens, rental car companies or business-class road travelers.

Century is powered by a stalwart 3.1-liter V6 that makes 175 horsepower while delivering an impressive 20 miles per gallon in the city and 30 miles per gallon on the highway. A smooth-shifting, electronically controlled four-speed automatic transmission puts the power to the pavement through the front wheels. Traction control and antilock brakes are both standard.

Inside, occupants will find plenty of room up front, with somewhat limited legroom a concern for backseat riders. Seats feel plush at first, like a big, poofy couch, but after sitting in them for a while, plush becomes mush. At least driving the Century is easy. Start it, engage a gear, plant your foot and go.

The Century comes standard with such features as remote keyless entry, automatic climate control, programmable power door locks, power windows, daytime running lamps with Twilight Sentinel (which automatically controls the headlamps based on lighting conditions), tilt steering wheel, door courtesy lights, battery rundown protection, a tire-inflation monitor and a theft-deterrent system. OnStar in-vehicle safety, security and information service is standard on Limited models, along with a driver side-impact airbag, cruise control, leather seats (power adjustable for the driver), floor mats and sporty variable-effort power steering.

Not much has changed for the 2002 model year. Special Edition models with front bucket seats can be ordered with a new center storage console and all Centurys get LATCH child seat anchors and an improved cruise control system. Painted aluminum wheels have been added to the Special Appearance package, and all Limited models get woodgrain trim around the door switches.

The Century stacks up decently in the high-volume midsize sedan market, where it shows continued sales strength against its domestic rivals. A laudable safety record and solid build quality make it an enduring favorite, while earning it ''top buy'' acclaim from more than a few consumer publications and rating organizations along the way. With the highest customer-loyalty rating in the segment, Century buyers seem prepared to stick with this Buick well into the new century.