I personally prefer 2WD. I look for trucks that have limited slip instead of
4WD. Better gas mileage is one benefit, less to break is another as well as
lower insurance rates. 2WD also costs about $2k less up front. Resale is
easier w/ 4WD, but I don't buy something with the mind of how will it sell
wayyyy down the road. I look for what I need and want to have to use every
day. 4WD is very nice on the occasional big snow we get, but for me, that's
about its only use.

Depends on your climate, off roading habits , and other relevant use. I
would never go back to a 2WD. I find it hard to believe that my Avalanche in
2WD mode is getting worse mileage than a similar 2WD Tahoe.

With a locker you can take a 2wd pretty much anywhere a 4x4 can go.  The
main downside is the lask of low range, I found that to be hard on the
transmission.
There really isn't any extra maintenance and the gas mileage is so close it
doesn't make much of a difference.

Back in September 2005, when GM was offering their "below invoice" sale, I
shopped for a Chevy truck with the all-aluminum 5.3L V8.  The regular build
order put that engine only in a 4X4 with an extended cab.  I wanted the
engine, so I ponied up the extra bucks for the 4X4 and extended cab.  So
far, I haven't used the 4 wheel drive but the extended cab is really handy.

I had a 4x4 Jimmy for six years (and 150K miles) and only found the need to
use the 4lo once.

The rest of the time, I delt with the stupid actuator going out on me.

Ever since I've had my Avalanche, I've taken it all sorts of places
I'm "supposed" to have 4WD but have yet to get stuck.

Oh, and I had even taken my 2wd minivan way out off roading without a
problem...

http://www.perfectreign.com/?q=node/17

...that picture was taken right next to where all the 4x4 Jeep tours would
go.  :P