As Huskerville said, it really does depend on what you want.  As far as the Dodge goes, go with a Cummins, there is no comaparison from a diesel to a gas engine.  The Cummins is a very reliable engine and I have seen many with over 600,000 miles if properly taken care of.  The Dodges have common problems with the front ends having parts go bad repeatedly (this is why I quit buying Dodges) The GM Duramax engines did have trouble with injectors on the early models (01-04.5), not so much on the newer ones.  As a Duramax owner, I can attest to the almost $4,000 cost to replace the injectors in my engine (new GM/Bosch injectors, not reman).  With that being said, most of the early engines have already had injectors replaced and should no longer be an issue.  I've never been a Ford person, so I can't comment from firsthand experience, but have never heard anything good about a 6.0L.  I've heard the 6.4L isn't much better.

Keep in mind with any diesel, regardless of make or brand of truck, maintenance is much more costly that with any gas engine.  If you will use the truck to pull on a regular basis, a diesel is worth its weight in gold.  I personally would never own another gas engine, but that is just me.  Do your research and get whatever fits your needs the best.

That must be a East coast thing,,   On the Western freeways I would say that Hotshoters prefer the Dodge Cummins over  Ford and GM combined by 3 to 1 easy..  

Back to the topic,  The gas engines will be fine for you, just be aware that the place for the Diesel engine is TOWING they are ment to be worked.  Generally you are better off with a gas rig if you only tow ocasionaly.  If you are going to tow heavy and often consider one of the Diesels.    I am on my 5th Dodge Cummins and have had excellent service from them.  I have friends that LOVE the GM Izisu Diesel with the Allison transmission.   My sister has two 6.0 Ford diesels . Beautiful trucks  BUT They have been a money pit for her, lots of minor problems and a few big items.    Cost her MAJOR money to repair both of them when they were out of warrenty.  Being a diesel mechanic by trade I am very picky on what I reccomend.

I went from an 02 cummins to an 08 Duramax

If you want an automatic,  the Duramax w/ allison trannsmission is excellent.  I tow almost daily and their tow/haul mode is second to none for slowing down (i only click it on when slowing down)  and you also have a manual gear lock out, once again very nice when slowing down.  lets the truck do it slower so less brake use and easier on horses.   I'm not a fan of where the fuel filter is....some idiot put it behind the fenderwell so a real pain to change one when you gel one up.  

02 Cummins:  5.9  with a 6 speed manual.  was a nice truck but a real piece of junk at the same time.  my buddy had an 00 cummins 5 speed and his was awsome.  I took care of mine, he abused his.   mine was assembled in MEXICO!!!  his in USA.  so I would make sure no matter what vehicle check the individual vehicle's assembly location, New or used.  my old mechanic had lots of troubles with fords & dodge's assembled in Mexico.   Fuel filter was a breeze to get to and only about $10 vs chevy's $65.

for fuel milage, the Duamax is actually pretty friendly for a daily driver.  On trips between NY & PA without a load I can get 20-22 almost every time.  Around town/farm 16-18.  Towing anything i'm between 11-13  but i'm also not easy on the throttle with most of my towing unless i have the horses on and have some long hills to pull most days.

ford...terrible dealer in my area so don't really know much.