3:55, I wanted 3:92 but settled on 3:55 because I really did not need 3:92 at the time and the truck had pretty much everything else I wanted. #3:92 would be nice to have now that I am towing a heavier trailer, but the 3:55 have performed amazingly well.
3.21 ratio v6 4x4 longbed Ram1500 8 speed trans. I specifically wanted this setup to maximize fuel economy (avgs 21mpg mixed driving )and it works great. I travel 75 miles a day and often go 75mph+ on the highway 5 days a week to work. Truck is better on gas and faster than my old 98 Ram1500 with 3.55 rear and 360V8 (only got 12mpg)