Almost any of the motors you mentioned would be good. The big thing is gas vs diesel. Diesel, especially the earlier years (2002-2006) will return far better fuel economy towing and non towing and have a longer service life. Some of the gas motors you mentioned do have a history of oil consumption and spark plugs blowing out of the heads. It really is going to depend on year of truck you want to buy, miles already on the ODO, price, condition. If I were looking today for a newer truck, and knowing what I know today it would be a 3500 series 5.9L Cummins of 2006 or 2007 vintage. The Cummins is a true commercial motor and with proper care will go 500K miles without breaking a sweat. But to find one of those is going to cost you more than most of the others. And honestly possible more than a newer 6.7L Cummins.