After researching and talking to many people I purchased a 2007 Chevy 2500HD Classic 6.6L diesel. This truck will pull anything. I pull a 7 x 16 tandem trailer that is around 6500# when loaded with my equipment. The truck doesn't have any problems pulling it. I get about 12.5 MPG when pulling. I get around 17 MPG when driving on the highway and in between when mixed driving.
I am currently looking for a gasser. After my large loan payment, expensive oil changes, and $4 diesel, I can afford the lower mileage I will get driving a 2500HD 6.0 or a Toyota Tundra 5.7. Just a quick note. Both of these trucks offer flex fuel on newer models.
I hate the idea of giving up the diesel but its hard for me to justify it economically.