My dad has a 2003 Ram 2500 with the 5.9 and it has 130,000 miles on it. He had to put injectors in it last year but otherwise has been a great truck.
My brother has a 2006 Ram 2500 with the 5.9 and it has maybe 30,000 miles on it. Yes...just 30,000 miles. He really only uses it to go hunting and to haul firewood, which he heats his house with. Otherwise it sits in the garage. He's had several offers on it but it would take crazy money to get it off of him.