I have no particular preference, having driven them all. That being said:
1. Proper Maintenance: If you do it properly and regularly, generally Ford/GMC/Chevy have lower maintenance costs per year average. Toyota and Nissan both have less frequent needs, but tend to be much more expensive. If you do your own maintenance, be sure to investigate what is easiest work on. These days, more is packed in less space under that hood, so you need to know if you have to do any work on a truck, what you can and cannot get to easily. Also, you're more likely to have Toyota or Nissan cover recalls and defects for free than GM, Ford, or Dodge. However, what they won't cover is expensive.
2. Buy Used (preferably dealer cars): I know this is an unusual sounding piece of advice, but usually most of the major flaws in a vehicle come to the surface after about a year or two (once the heavy drivers start to get near triple digit mileage). For instance, there was a flaw in the sending unit on the fuel gauge in 1999-2003 Chevy/GMC trucks and SUV's that caused it to fail, making the fuel gauge needle unreliable. It was a known issue after about two years, but it wasn't recalled so it would cost almost $400 to fix the problem. What a pain! Hence, look for a 2008 or 2009 model year truck and research what kinds of problems are known issues and what it takes to fix them. Far better than discovering your new truck has a serious flaw and then being forced to pay to fix it.
3. Gas Mileage: Forget about it. Don't even look at it as a comparison item. You're going to blow through gas like smoke.
4. Know Your Needs: Let's face it, I own a 2001 Silverado 1500 with the 5.3L V8 and
a road geared differential! That's right, no tow package, no 4x4, nada. I can tow up to 500/5000 tongue/trailer and not have any problems. I don't ever tow anything that big though. The biggest problem with towing is being able to STOP, NOT PULL. If you aren't going to be towing anything more than a family boat or something small, and aren't going mud riding, there's no reason for Z71, Fx4, 4x4, or any of that stuff. If you live somewhere that you need 4WD for snow, that's a different story, but still you don't need a 6-7L diesel monster. Don't buy more truck than you need, it's an utter waste of money, no matter how cool it looks!
5. There was something in my mind here, but I forgot it already so I'm reserving this for future comments
