Sounds to me like the OP. based on his needs should buy a crew cab long bed truck. He has a preference for Ford products, so I would recomend a Superduty 250 or 350, probably a 4x4 since he lives in snow country, I would also recomend these options, posi rear diff, integrated trailer controller, skid plate package, [Greatwhitehunter, you know he goes off road based on his user name], power windows and locks,power slider, the entertainment package with the flip down TV/DVD player would be a godsend to keep the kids occupied on long trips while going camping, and remote start because diesels take forever to warm up in the winter, and a HD rear sway bar package.
As far as which to buy, 6.0psd or 6.4psd used, I would lean more toward the 6.4 despite its thirst for fuel and emissions, simply because some of the 6.0psd's had some issues, and while many honest TBN members have had fantastic luck with they're 6.0's, Few can argue the fact that some of the pre 06's were real headaches, and some were not. Unless you know the previous owner of a used pre 06 6.0, it is real tough to tell what you are buying, a headache or a engine that will outlast a twinke.
If you could hold out for another month or so, you might be able to get a better price, new or used, due to the fact that 4x4 sales usualy slow down in the spring, as well as dealers trying to make room for the new model year vehicles. If looking for used, you may try googling something like For Sale Ford crew cab diesel 07 Craigslist. Many times this is a way to backdoor a nationwide craigslist search, since craigslist makes you search regionaly and it takes forever.
For the record I currently own a DMax, but I owned a v-10 Ford SD for 100k and loved it to, never owned a ram, but I would not be afraid to if thats what I like. Besides the mileage issues all the new light truck "clean" diesels have, I just don't like how tight the Ford engine compartment is. That being said, it is because I am a experienced professional tech who is about as FRUGAL as they come, and I insist on doing all non warranty work myself. If I was not going to work on it, like many people don't, I would care less how it looked under the hood.