RE: ram 1500
I've owned both a 1500 with a 4.7 and I have a 2500 with the Cummins diesel. Buy the diesel and never look back. The 4.7 was a dog and the gas mileage royally sucked. I have the 3/4 ton with the Cummins and it pulls my boat which is over 8000 lbs. and has no problem whatsoever, has a lot more to give than that, and the gas mileage is great.
I have a buddy that has a Chevy with the big Duramax with the Allison transmission and it is one bad truck. Mine is an 2005 and his is a 2007. I like the interiors of the Chevy better too.
Get a diesel whatever you do and you won't regret it.
Hopefully that helps.