Justaplain said </font><font color="blue" class="small">( For a lot of 4.5 Acres you are wasting money on anything bigger than 20 HP. )</font>
While I might have worded it a little gentler, I have to agree with Justaplain's view about smaller CUTs vs buying as much horespower as you can afford. I wouldn't call it wasting, but it could get to a point of over-kill. Buying as much horsepower as you can afford has to stop somewhere or you'll end up with a Stieger that won't fit on your driveway. The money saved can be used for more implements. And, smaller tractors have the advantages of getting into tight places easier and causing less damage to the landsape, once it is established. They are easier to work on. They require less fluids. The implements are easier to handle. They fit in your garage. They can be transported much easier. They aren't as intimidating to newbies, etc...
You said </font><font color="blue" class="small">( My uses will be mainly maintaining a gravel drive , digging post holes,plowing snow on about 4.5 acres . )</font>
The gravel in your driveway will only be maintained a few times a year if it is installed correctly. Mostly filling a few ruts or cutting down a crown. Post holes might be a problem, depending on your soil type, but that could probably be overcome with the correct bit on the PHD. The right tool VS just throwing more HP at it. Snow plowing could be a problem, but even a small CUT can handle an FEL or blower that could do the job most of the time. Blizzards are extreme examples.
I would make a detailed report of all the jobs you need to do now and will need to do in the future. Then determine what size tractor will do those jobs in the amount of time that you are willing to spend on them. Then, for peace of mind and insurance, purchase the next size up tractor. Just my opinions. Good luck and keep us informed as to your decision making process.