Truck shopping 04-07 model years. Advice please.

Any of the 5.9L Cummins equipped Dodges will give you years of reliable service for minimal outlay. The GM Duramax/Allison combination are also reliable well built vehicles. Go drive them and compare cost, ride and comfort, then make a decision. Personally i like my Cummins, 25% fewer moving parts, lower revving and the motor is proven over millions of miles of satisfied owners.