GMC's full-size pickup has been around in one form or another since the early '60s. Currently in its sixth generation, the GMC Sierra, as it's now called, boasts classic styling and a wide variety of body styles and drivetrain configurations. A perennial competitor to the full-size offerings from Ford and Dodge, GMC now positions itself as the professional-grade truck in GM's lineup. Although its sales numbers are far below those of its competitors, when combined with its sister vehicle, the Silverado, sales of the two trucks outdo the F-Series.

Often first to market with unique innovations, the 2006 GMC Sierra 1500 continues that tradition with nationwide availability of the hybrid-electric model. GMC trucks also offer the OnStar communications system that provides the convenience of 24-hour on-call assistance for everything from tow truck requests to dinner reservations. Combine this with modern styling on the outside and a host of features on the inside, and the half-ton Sierra presents a compelling package for anyone in the market for a well-rounded full-size pickup. The Sierra 1500 is really starting to show its age, however, compared to the newer full-size offerings from Dodge, Ford and Nissan. And all three trucks have the GMC Sierra beaten when it comes to interior design and materials, and overall refinement. We strongly encourage you to try out the competition before you buy.

The GMC Sierra 1500 offers three cab styles are available in four different trim levels and two bed lengths. Regular cabs can be outfitted with Work Truck, Base or SLE1 trim, while extended cabs come in Work Truck, SL, SLE1, SLE2 or SLT trim. The light-duty crew cab models are available in either SL, SLE1, SLE2, SLT or Denali trim. True to their name, Work Trucks offer only the basics, but you still get manual dual-zone air conditioning and ABS. SL Sierras include a few more amenities like cruise control and a CD player. The SLE1 trim adds upgrades like power windows and locks, remote keyless entry and foglamps. The SLE2 adds automatic climate control, Bose audio and a power driver seat. SLT trucks add aluminum wheels and leather upholstery. Top-level Denali models include nearly every available option as standard, as well as unique trim and a 345-hp V8 engine.

Several engine choices are available for the 2006 GMC Sierra, ranging from a 195-horsepower, 4.3-liter V6 to a 345-hp, 6.0-liter V8 in the Denali and VortecMAX package. In between, you'll find a 285-hp, 4.8-liter V8; a 295-hp, 5.3-liter V8; and a 310-hp, 5.3-liter V8. All Sierra trucks come standard with a four-speed automatic, except V6-equipped regular cabs, which come with a five-speed manual. The maximum towing capacity with the 5.3-liter is 8,300 pounds, while the Denali is rated at 8,100 pounds. On SLT extended cabs and crew cabs with the 6.0-liter V8, the max rating is 10,000 pounds. Either two- or four-wheel drive is available on all models; the Denali comes with all-wheel drive. A hybrid powertrain option is available on SLE extended cabs with the 5.3-liter, but the system does not provide any power boost. Its main function is to conserve fuel via automatic engine shutdown and startup at stops, as well as provide on-the-job power through four 120-volt AC outlets.

Four-wheel antilock brakes are standard. In government crash tests, the Sierra 1500 earned four stars (out of five) for driver protection in frontal impacts and three stars for the front passenger. In IIHS frontal offset crash testing, the Sierra was given an overall rating of "Marginal" -- the second lowest of four.

The GMC Sierra 1500 is comfortable enough to be a daily driver, yet it's still powerful enough to use as a dedicated work truck. Acceleration ranges from adequate to vigorous, depending on which V8 you select, and the automatic transmission shifts with authority. The steering feels vague on center, but it's light and precise enough for easy maneuvering. The automatic engine shutdown and startup feature works seamlessly in the hybrid truck.

Inside, Sierra 1500 buyers will find a logically laid-out interior, with clear, uncluttered gauges. Materials quality is unimpressive, and build quality, though improved over the last few years, is still below that of the competition. The cabin is roomy, particularly on crew cab models.