Re: V10 VS 7.3 diesel
I would avoid the 6.0L diesels, even with the EGR deleted. Go to
Ford Powerstroke Diesel Forum for any reason why. They are problematic. Many have had no issues, but far more have had major issues. Unless you have the expertise to repair yourself, they can get very, very expensive to have work done. When working properly they are great on fuel and power...they can be had for $10K less locally than a comparable Dodge Cummins equipped 3/4-1 tons. The 5.4L gasser is actually a decent little power plant (better mileage vs. power ratio IMHO comparing to the V10). The V10 get 10-12mpg unloaded at best and the power is anemic at best (compratively speaking).
The 7.3L diesel is a great motor as a whole. It's relible, has decent power and gets decent mileage. (I credit the diesel desire for FORD based on the predictability of this motor) My step-dad, who's a retired truck driver, cusses me to this very day for making him trade-in his 1995 F250 4x4 for a 2004 F350 4x4. He had a broken crank shaft and multiple injector issues with the 6.0L...the 7.3L nothing (over 110K on the 7.3 under 73K on the 6.0). I should say by 2006 Ford had most the bugs worked out of the 6.0L, but there are still issues!
Of the 2 choices you've presented, go with 7.3L diesel! you'll hate the anemic power poor fuel mileage of the V10.
These are my opinions based in my experiences. NOT gospel!