A choice of V8 engines is available, two of which are versions of the Vortec 5.3-liter V8, and which can run on E85 ethanol. The new generation 5.3 with an aluminum block, the engine in our test SLT, makes 310 horsepower and 335 pound-feet of torque. The more powerful optional engine ($1095) is an all-aluminum 6.0-liter V8 with variable valve timing, making 366 horsepower and 380 pound-feet of torque.

The Yukon XL Denali ($49,970) comes with a 6.2-liter V8 making 380 horsepower and 417 pound-feet of torque, a six-speed automatic with manual mode, all-wheel drive system, and the AutoRide active electronic suspension.

All other Yukon XLs use a four-speed automatic transmission, available in three strengths, depending on whether the XL is 2WD, 4WD, or 2500. They all have a Tow/Haul mode, which reduces upshifting and downshifting, and also shifts quicker, so the transmission doesn't work so hard when pulling a big load. Transmission oil temperature is part of the instrumentation (along with a tire pressure monitor).

The SLE comes standard equipment with cloth interior, six-way power driver's seat, 60/40 second row bench seat, two-passenger third row seat, three-zone climate control, AM/FM/6CD/MP3, rear seat audio and climate controls, power windows and locks with remote entry, cruise control, heated sideview mirrors, 17-inch aluminum wheels, roof rack rails, deep tinted glass, foglamps, and last but definitely not least, a tow package including heavy hitch, seven-pin wiring harness, two-inch receiver and electric brake control harness. Also standard is GM's OnStar system, which, among other things, notifies headquarters if there has been a crash, and someone calls the vehicle and sends help if necessary.

The SLT package ($4135) includes leather interior, 12-way power heated bucket seats in front, power adjustable pedals, remote starter, Bose sound system, XM satellite radio, garage door opener, power folding sideview mirrors, rear parking assist beeper, and roof rack crossbars.

Safety equipment on all models includes dual frontal airbags, four-wheel-disc anti-lock brakes with electronic proportioning, and StabiliTrak, GM's electronic stability program with anti-rollover mitigation and traction control. Full length airbag curtains are optional (standard with SLT), but front side airbags are not available, which is surprising, given the competition and price. The XL earned the maximum five stars in the government's head-on crash tests.

Options include a navigation system ($2145), rear-seat entertainment system ($1295), power sunroof ($995), second-row bucket seats ($490), power release for those seats ($425), power liftgate ($350), rearview camera monitor ($195), three-passenger third-row seat ($100), heated washer fluid system ($85), and 20-inch polished aluminum wheels ($1795).