I know you're tired of hearing about grounding issues, but I had the same problem and after changing the starter and cables I still had the same problem.
Side post battery terminals. Very convenient but a lossy connection. Next time you try and have nothing but clicking, try to move the ground acble terminal ends at the battery.

 

mudmaniac..What do you mean by moving the ground terminal on the battery side? Switch it to a top terminal connection battery VS. a side post?

 

I said that wrong.
I have found that the side terminals can be troublesome, the female threads on the battery terminals are not very deep and they are easy to strip out, if the terminal bolt is a little too long you can feel like it's tight because it has bottomed out, you can check this by trying to move the cables after tightening. My reference to the top post battery terminals is just a preference in style I have for them.
My problem was that I could hop in the truck and turn the ignition on and all electrical systems would look fine, but when I would try to crank I would just get a click.
I changed the battery, cables and starter only to have the same problem come back up. I finally figured out when trying to jump start it that on the posiitive side I had 2 terminals stacked over one another and even though the terminal bolt would tighten up, it was not compressing the terminals tight enough to carry and cranking amps.

 

If you have a solenoid directly attached to the starter, try bypassing the vehicle wiring with a hot wire directly. If the starter rolls, your problem is in the vehicle wiring. If it does not, then the solenoid is likely the problem. (It wouldn't be the first time)

If the problem is in the wiring, trace it backward from the starter and try to activate it with your hot lead from the other end of the wire. You might also use your VOM to check for current at the solenoid.

It sounds to me like a faulty solenoid, and your vehicle wiring is just fine.

 

Thank you all for the replies. All the connection leads are solid and tight. It seems to me there is either a short some where or a defective battery(even though it is a brand new OPTIMA red top gel cel starting battery). Like I mentioned before, if it is jumped from another vehicle the starter cranks strong and the engine starts. I disconnect the jump wires let it run for about 5 minutes, check the output from the alternator and Im reading about 13.7 volts. I let it sit for about 10 minutes (turned off), thengo to start it again without the jump and same symptom (very weak starting followed by clicks). With these tests, it eliminates a defective starter/solenoid or grounding issues. Would you all agree with that? Let me know what you think, I will post again as soon as I can. [&:]

 

You might try having the new battery tested (a load test), I have seen many times where a new battery was defective off the shelf.
Also since you can jumpstart and it spins over fine, I would look very closely at the connections of the cables at the battery.

John