My thinking is that if you don't know whether you need 4 wheel drive or not, you don't need it. Personally I tow quite often in the snow wouldn't be without it there. When empty, the handling on dirt roads, snow etc is considerably better with the 4 wheel drive when engaged, provided you remember while you have better controllability, it doesn't help with braking.
On the downside, when you get stuck in the sand or mud with a diesel 4X4 you tend to really be stuck and are going to have a heck of a hard time getting out. The newer 4X4 pickups also tend to have a ton of expensive stuff underneath that is easy to hit or damage, and they tend to be very long so they aren't really a good choice for off-roading. The other downside is that the suspension on 1 ton trucks are terrible when it comes to travel, and ability to keep the tires planted on rough roads when empty. They ride and handle terrible on dirt roads, especially the washboarded ones. I wouldn't be without 4X4, but they aren't necessarily for everyone.