I purchased my truck new with 4WD. I've only used 4WD a few times in the past 6 years but during those episodes I was glad I had it. I had other reasons for wanting 4WD: It may help when it comes time to sell the truck (especially in some parts of the country where 4WD is a necessity), and the truck sits a bit higher, which I like.
It can probably be said that 4WD isn't a necessity for many folks but having it available can make the difference between easily getting out of a situation or having to be towed out.