How many miles do you really put on your truck? If you take the money you will spend on new rear gears, or a T5 swap, or whatever, and then calculate how much fuel you could buy with that money you might find that leaving things as they are might just be the best route.
That being said I can never leave things well enough alone on my truck. Here is a link to an excellent gear ratio chart that you might find helpful.
Good luck
http://www.sierrabronco.com/TireGearRatio.htm
