Thank you all for the replies, much appreciated.

The fan clutch is spinning freely with engine off, so it is not siezed up, but an excellent thought that I missed. I am beginning to believe what Dave posted about the water pump not pumping enough warm water through the system. I was out today with the truck and got it up to normal operating temp, as soon as I pulled into the driveway and let the engine idle, the temperature started to drop down towards the Cold mark, and rather quickly I might add. This leads me to believe it is a circulation problem dependent on engine speed. The impeller is turning somewhat at the higher rpm's, but at idle and lower rpm's it is not turning at all and not circulating the hot coolant through the system.
Now the problem I have with my theory, and Dave's, is why isn't the engine overheating at idle if the impeller is not circulating the coolant? Wouldn't it get overly hot from not circulating through the radiator and getting cooled off? Last two days temps here have been between 20 and 30 degrees, not bitter cold and normally the truck would heat up fast in these temperatures. Also why when turning on the heater it cools off even faster at idle?
I am not about to start changing parts indiscrimantly if I am not completely sure if that is the problem.

As for what one post said:

"did you put the proper temperature t-stat in?

#3 the coolant is suppose to be changed every two years. have you flushed the system?

#4 do a compression check to make sure everything is sound"

I kind of ignored any of this. The parts store only had one listing for thermostats for this vehicle and it was the standard temp thermostat.

Coolant is NOT supposed to be changed every two years, yes you can change your coolant every two years if you want to waste money and time doing it. Coolant will last as long as 5 years or more as long as your cooling system is functioning properly. Prestone guarantees 5 years minimum for their coolant. I have known people who NEVER changed their coolant and NEVER had a problem. Whomever says your coolant must be changed every two years must work for one of the coolant manufacturers, lol.

I have no signs of lost compression, engine runs great, no loss of power, and no signs of anti-freeze mixing with the oil.

I still have to think about the water pump theory or still could be as simple as an air lock still in the system. I might just drain the system and start over again, not because the coolant has gone bad, but because it may be the only way to get rid of a bad air lock.