The extended cab has two rows of seats with rear-hinged rear access doors that open 170 degrees and have roll-down windows. The extended cab can be equipped with either a short bed (5-foot, 8-inch), standard or long bed. The extended cab can be equipped with seating for five or six.

The Crew Cab has two rows of seats and four front-hinged doors, like those on a Yukon. The Crew Cab can be equipped with seating for five or six and comes with the short bed.

Standard equipment on the basic WT 1SA work truck ($18,045) includes vinyl seating surfaces, air conditioning, AM/FM/XM radio, one-year of OnStar, daytime running lights, tire pressure monitoring system, Smooth Ride suspension, 17-inch wheels, automatic transmission and chrome bumpers.

SLE ($25,575-$33,375) adds cloth seats, CD player, cruise control, rear-window defogger, auto-dimming rearview mirror with compass and outside temperatures, leather-wrapped steering wheel, fog lamps, handling/trailering suspension, carpeting and power door locks/windows/mirrors. Additions include premium cloth seats, dual-zone air conditioning, a floor console, six-way power driver and front passenger seats, audio controls on the steering wheel, and machined aluminum wheels.

SLT ($33,580-$40,575) adds leather seat trim, a unique instrument panel, six-disc CD changer with Bose sound system, heated windshield washers, front bucket seats with 12-way power adjustment and heat, and polished aluminum wheels; crew cab models also get a rear-seat audio system.

Denali ($42,740) includes a top-flight interior with leather, heated and powered front seats, unique woodgrain console, side curtain airbags, dual-zone climate control, park assist and so on. Denali options include a heated steering wheel, heated/cooled front seats, sunroof, and rear-seat entertainment. Denali comes only as a Crew Cab with a 403-hp 6.2-liter V8 engine, six-speed automatic transmission and rear or all-wheel drive.

All Terrain model features the Z71 off-road package, heavy-duty trailer package, 18-inch wheels, Rancho shocks, and myriad cosmetic enhancements. When ordered with SLT trim, exclusive two-tone leather is used. All Terrain is available as an extended cab standard box or crew cab, 2WD or 4WD with 5.3-liter or 6-liter engine.

Sierra Hybrid, Crew Cab only, uses a specially tuned 332-hp 6-liter in conjunction with a battery pack and four-speed automatic transmission that houses two electric motor units. With EPA ratings in the 20-22 mpg range its urban economy is the best of the Sierras, the compromises being price, payload (max mid-1400-pound-range) and maximum tow capacity around 6000 pounds.

Options include a locking rear differential, StabiliTrak, towing and trailering equipment, and a power sunroof.

Safety features include dual front airbags and a tire-pressure monitoring system. Optional head curtain airbags automatically inflate when sensors sense a severe impact to provide extra protection in the event of a rollover or secondary collision. Also available: driver and front-seat passenger side-impact air bags; anti-lock brakes, StabiliTrak electronic stability control with rollover mitigation technology, Autotrac active transfer case, ultrasonic rear park assist, OnStar emergency notification.