Well here's what I think I know and some other info on the subject
Talking pickup trucks:
As already stated 2WD stinks in bad weather, wet grass, mud, sand, all the camping environments.
- The Big 3 push 4WD since it drives up their profit margins and almost all new pickups are 4WD.
- As with many things the newer trucks are more efficient and the 4WD version tends to run about 300# heavier than the 2WD version.
- The newer trucks get better fuel mileage due to more powerful engines and higher gear rations so the difference in mpg these days is around 1 mpg.
- Diesels handle 4WD better than gas engines in my opinion due to their higher torque.
- 4WD pickup ride about 2" higher to get additional clearance for both the front axle and ground clearance (assumes you are going to leave the road)
Personal experience I've owned Ford pickups
1980 F150 4x2 got stuck every winter or when I left the pavement.
1992? F150 4x4 never got stuck and got me to work everyday. Underpowered engine and drank gas at 10 mpg avg.
2004 F350 4x2 diesel pulls and rides well but will get stuck looking at wet grass or loose gravel.
If I bought another pickup for towing my camper it will probably be 4WD. I'll give up 300# of cargo capacity and tow capacity to avoid the hassle of getting stuck in the campground. If I bought a "grocery getter" (shiny 1500's people drive like cars) I'd probably buy a 2WD.
Remember 4WD gets you going better but does nothing more to stop you
When you need it, 4WD is worth every penny. Otherwise, it's wasted money.
4x4? 4x2? Part-Time 4WD? Full-Time AWD?
http://4wheeldrive.about.com/od/offroadatvbasics/ss/4wd-2wd-difference-between-4x4-4x2.htm