The Wagon Queen Family Tricksters
What Jeep started with the Wagoneer in the early '60s (and even earlier with its first wagons in the '40s) and are now called SUVs are exactly what most wheeling families need. They offer plenty of rugrat room and wheelbase for hillclimbing without scaring the missus. Fullsize Cherokee, Bronco, Blazer, or Ramcharger doesn't matter, just take your pick. I'd look for a model from the '70s so it would have a solid axle and a decent transfer case, could be lifted easily, and would be inexpensive to own. These trucks are just that, trucks! They come with fullsize truck dimensions, frames, and features. Gas prices be damned! They're not cute carlike crossovers or skier-shuttling transports with stuck-on AWD badges and toothpick axleshafts.
Modern-day versions such as XJ Cherokees or Grand Cherokees (ZJs and WJs) are quickly replacing the older fullsize SUVs. Just remember that, although they have solid axles and two-speed transfer cases, they are unibody (no separate frame) and are built with much lighter-duty components. Still, they can wheel the family in comfort and make excellent dual-purpose vehicles.
The Young Guns
Just so you don't think I'm an old guy who's blind to the newer 4x4s, my favorite late-model trucks are the new Dodge Ram Power Wagon and Jeep Wrangler Rubicon (including what I've seen of the '07 model). Note that even though they're new, they still have strong solid axles, true low-range gearing, lockers, and plenty of ground clearance for 98 percent of the trails out there.
Although they may be pricier to obtain at first, think of the fact that these two 4x4s come so well equipped they almost don't need any modifications. My back and my family are telling me I need one...now. I guess these two trucks make my list agree, at least partially, with Jerrod's. See, old or young, age doesn't matter. Let's all just have fun doing what we have in common: Get outside and go wheeling!