I kind of recall an earlier thread where you mentioned growing wheat? For most tilling (plowing, discing etc) the tractor will be light on the front end and 4wd will be of little use. Most tilling and harvesting should also be done when the ground is relatively dry, so again 4wd is not a big deal. If you are working in wet/muddy or slippery conditions, especially with heavy loads in the loader 4wd will be a big benefit.
For the horse power rating you are looking at and your intended use though, I would still be looking at something older. In the later 60's and early 70's 50 to 60 hp was considered a fairly large farm tractor and they were made with enough weight for tilling. These days most farmers would laugh at the idea of tilling with a tractor that "small". The newer tractors in that hp range are really not intended for "field" work, more "yard" work like moving stuff with the loader (manure, silage, round bales). mowing with a bush hog. blowing snow etc. Think of it like this, how does a 10hp GT from the late 60's to ealy 70's compare to a new 10hp "gt" (riding lawnmower)? Most farms have gotten bigger and guys are trying to till/plant/harvest more acres in the same amount of time, so the machines and implements have gotten bigger as well. You mentioned (if I remember right) farming on a scale similar to what was done back in the 60's to 70's. I think you will find that older well maintained equipment will not only cost less, but perform better than most of the new stuff in the same size range.
Good memory, I am starting a small farm for growing organic old fashion varieties of grain like wheat, corn and ect. I will be pulling a plow, disk, spring tooth, cultivator, planters and who knows what else I decide to tie to the back of it.
I already have some older tractors, I would like to get something new so I can have a nice tight cab and not have any worries (although the old tractors are probably more reliable lol ). All the old tractors I have are half worn out, loud, cabless and rattly. A friend of mine (bigger farmer) has a old (70's no cab) 130hp John Deere and he uses it to do hundreds of acres of hay, that one tractor does all the swathing, raking and baling. Although he has 2 new JD's (one 80hp and the other is 150hp), he still prefers the old JD with the umbrella.
I will use my other older tractors, but this new one will be my long use tractor, something I'm in all day for a couple weeks, something I can kick on the A/C, radio and just sit back and enjoy the ride!