WooHoo MarkV, are you me? Your post that begins "WELL HERE'S THE THING FELLAS...", I coulda written that. Sub Ford 4000 for the 3600 and JD40 for the F-Cub and we're the same person! Instead of 'valve job and reringed' mine is 'rodents ate the electrical system' /forums/images/graemlins/grin.gif. Like you, I just got tired of tinkerin' with the old stuff when real work needed doin' and wanted something new and dependable.
And up until recently, my attitude toward 4WD was the same as yours too. Years of gettin' the job done with 2WD was proof, to me, that 4WD wasn't needed.
But, when I bought my new tractor, a very basic Kubota
L4300, it had 4WD anyway. Got to thinkin' that anymore, I almost always work alone. There are no neighbors to help out if I get stuck even though I've still got the 4000 and the JD. I've gotta keep it goin' on my own. 4WD would help there. It has quickly gotten me out of a couple of tight spots already and I've only got 5 hrs on the machine. In fact, to my thinking, the time wasted on 2WD traction limitations was no different than the time wasted due to lack of parking brake (yep, got that one too) or due to a dead battery (bad voltage regulator).
Also noticed the CUTs are light, very light when compared to the Ag tractors I've run. Something has to make up for the lack of weight if the power's going to make forward motion. Light is nice if you have to trailer the rig, which I do. Might not be an issue for you.
But even when going heavy 4WD is nice. Got a fair amount of time recently chisel plowing with a NH8970 4WD. Nothing would stop that thing. Those 4 big tires relentlessly clawing away was scary 'til I got used to it. By not wasting time with traction problems that thing did alot of work fast. Also plowed alot of snow at the airport with a NH TV140. Having 4 turning made a big difference when the snow piles got higher than the cab.
Like the guys say, if 2WD will do it for you, go for it. I just responded because you sound so much like I did a year or two ago. Good luck whichever way you go.
Bob