CHOOSE ONE AND WHY.  

Powerstroke for sure because it comes in a ford and the ford is the best built body, you wont loose the tailgate or fuel tank on the dodge or all of the plastic pieces on the chev.  but if i could i would have a cummins in a ford body would be my dream truck. because they are easy to work on and get huge power with less money.  

Cummins hands down!
beefiest internal engine parts, simplest in design, longest lasting, easier to add horsepower, and the most options for go fast parts, Camshafts, turbo(s) injectors etc.etc.  

I drove a 1995 7.3 Powerstoke for 5 years and loved it - put 100k on top of the existing 200k, 90% towing. I now drive an 11 year newer Cummins and believe it is now the best diesel out there for any job - since ford screwed thier engine up with the 6.0. The perfect truck would be a Cummins with an Allison on a Ford body&frame with the luxaries and soft ride of a Chevy.  

Go with the Cummins for all of the reasons listed above. Chevy May offer the smoothest ride, but the independent suspension system that they use is just plain old weak compared to Ford and Dodge with the solid front axle.  

Are you talking engines alone, or engines and the trucks they come in?
And for what application?  

hotrodcummins:
Are you talking engines alone, or engines and the trucks they come in?
And for what application?

Engines and the trucks they come in. I will be using it as a daily driver, and will be pulling a trailer occasionally. This will be my first diesel truck and I'm on the fence on which one is the best all around truck.  

buy a dodge because it,ll outlast@ outperform any thing else  

Alot depends on what YOU want in a truck.
if you want a smooth carlike ride, go with GM. Ford definatly offers the best body for pulling trailers, and the most wheelbase/cab options. The 6.0 liter in my opinoin is junk, so if you buy a Ford, I would definatly go with the 7.3.
Dodge and Ford both offer solid axle front ends, while sacrificing ride quality, are much stronger and more reliable than the GM IFS, The dodge platform works best for ME, I'm a Diesel Tech, so I do all of the work on my truck, the Dodges are the simpest in design, in both the engine and the rest of the truck (GM and Ford tend to to get pretty crazy with all of their bells and whistles, more so than Dodge)
Are you buying a new or used truck, that will change the playing field quite a bit.  

You have got a good point. There is a good reason Ford doesn't put the 6.0 in there 650's and up. They put a real engine in them because the problem bound 6.0 can't hang. The Cummins is available in some of the mid-size trucks. Engine compartment wise, you can actually see the ground on the simple Cummins. The ford you got to take some plastic and other crap off. Not sure about the duramax. Keep in mind that the cummins is a case engine and the powerstroke really isn't much of an international engine anymore. The duramax I believe is either a mitsubishi or an isuzu, not sure.

Also I drive back and forth to Houston a lot and all you see Hotshots driving are the cummins powered Dodge and you know those engine are abused.  

hotrodcummins:
Alot depends on what YOU want in a truck.
if you want a smooth carlike ride, go with GM. Ford definatly offers the best body for pulling trailers, and the most wheelbase/cab options. The 6.0 liter in my opinoin is junk, so if you buy a Ford, I would definatly go with the 7.3.
Dodge and Ford both offer solid axle front ends, while sacrificing ride quality, are much stronger and more reliable than the GM IFS, The dodge platform works best for ME, I'm a Diesel Tech, so I do all of the work on my truck, the Dodges are the simpest in design, in both the engine and the rest of the truck (GM and Ford tend to to get pretty crazy with all of their bells and whistles, more so than Dodge)
Are you buying a new or used truck, that will change the playing field quite a bit.

I will be buying a used truck 04-05. My concern with the Dodge is the transmission. I have heard rumors that they have problems, but I have talked to people who drive them and they all say they never have had any problems. I am leaning to the Dodge but the Chevy is a close second.  

I did some asking around before I bought my Dodge, and the transmission issue came up. Rumor was a lot of the automatics would develop problems around 100K. I've got a manual, so I wasn't worried about it.  

I do not belive you'll have to be worried about the transmission. I read somewhere that Dodge has come a long way with thier automatic. Besides if an automatic will last 100K being pushed hard thats still not bad. Pulling heavy loads with one you will always have some problems but if you're worried go with a stick or the allison.  

Why would a manual transmission be more dependable than and automatic? I've noticed in 2 post replies people have recommended manual transmissions if I was worried about the automatics.  

Manual trannies have fewer moving parts than automatics, In the case of diesel pick-ups manual trannies always have cast iron housings.
Auto trannies rely heavily on the fluid, for lubricatoin/cooling, and for operating. The biggest mistake people make is not changing the ATF often enough, and when they finally do get around to chainging the fluid, the old fluid is broken down enough to the piont it has trouble mixing with the new fluid. That is why more and more repair shops are offering transmission flushes. it is impossible to change all of the fluid in an auto without either dissassembly or flushing the fluid.
The up side to an auto is they can be built to perform much better than a manual, it just takes lots of ***