Quadrasteer is no longer available on 2WD models, standard wheel sizes have been bumped up to 17 inches and, on extended and crew cab models, a power sunroof that includes HomeLink and a deluxe overhead console in now optional. GMC takes a step backward this year with the return of rear drum brakes, as opposed to last year's four-wheel disc setup. Big changes for the Denali this year -- Quadrasteer is no longer available, and the Denali is now a crew cab model only. A gasoline/electric hybrid model is also introduced this year. Basically a "mild" hybrid, the system provides no power boost, but does allow for automatic engine startup and shutdown at stops. This truck also comes with four 120-volt AC power outlets and is the only Silverado with rear disc brakes this year. The hybrid truck is only available in Western states and Florida.

GMC's full-size pickup has been around in one form or another since the early '60s. Currently in its sixth generation, the 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 Chevrolet Silverado, sales of the two trucks outdo the F-Series. Often first to market with unique innovations, the 2005 Sierra 1500 continues that tradition with options like the Quadrasteer four-wheel steering system and a new 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 is really starting to show its age, however, compared to the newer full-size offerings from Dodge, Ford and Nissan. The F-150 trumps the Sierra in terms of ride comfort, while the Titan and Hemi-equipped Ram hold a serious edge in power. And all three trucks have the Sierra beaten when it comes to interior design and overall refinement. We strongly encourage you to try out the competition before you buy.

Inside, Sierra 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.

Four-wheel antilock brakes are standard. In government crash tests, the Sierra 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 Sierra is comfortable enough to be a daily driver, yet it's still powerful enough to use as a dedicated work truck. Acceleration is adequate, especially with either of the Vortec V8s, 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. Additionally, the hybrid's electric power steering feels at least as good as the traditional setup.