Haven't been on here in a while and ran across this thread while checking back in. Here is the 07 2500 HD Duramax that I purchased brand new. At the time, GM had 12,000 off MSRP. I was bitten by the diesel bug and wanted a truck that I could drive for 500k miles. I keep my vehicles for 7 years or more on average. I have only owned GM vehicles, Camaro, 1500 SS Pickup, Z71 4x4, then the Dirtymax. I kept sticking with GM because of the deals I was able to get and they had been relatively trouble free. Not after the Duramax.
When I purchased the truck, I had hoped to be towing a boat back and forth to the Gulf Coast about 350 miles round trip on the weekends. Diesel was .50 per gallon cheaper than reg. unleaded. Then price went up to .20-.50 higher per gallon by a year after I purchased. I ended up getting a bass boat and stayed local even though I enjoyed salt water fishing. I got around 20-22 mpg hwy flat ground without towing. When I hooked up my 21' bass boat(probably around 4500-5k lbs) it dropped to around 13-15. I found as long as you keep it around 65mpg you will get best results. This was the extent of my towing.
Throughout the time I owned the truck I feel like I paid double what I would have paid over a Gas model. Even though "supposedly" it is less frequent maintenance, It seemed like when it did need something the price was 2x over gas so it evened out. I had various issues in the 6 years I owned the truck. I finally got tired of constantly having to fix things and I sold it and purchased a Japanese made vehicle.
I am not sure if this still applies to the newer trucks but you may have to plug in the engine block heater to keep the glow plugs warm in the Cold Mountain air. Also, in the winter time, don't count on getting good fuel mileage with the winter blend diesel fuel.
If you have to have the towing power of diesel then go for it, but if not I highly recommend a gas model. And whatever you do, don't tune the engine unless you want to deal with major problems at some point.
Good luck in your quest.