Tom, I have a 30hp tractor that I use and recently (2 years ago) got an even smaller 24hp tractor. Since buying the smaller tractor, it gets more hours than the larger machine simply because it can fit in the woods much better. At 12" shorter, I can fit UNDER branches that the ROPS on the on B2910 can not get under. At 15" less length & 6" less widht, I can cut nice paths in the woods that curve through them without having to clear wide swings at the corners.
When it comes to getting near the house and mowing around landscaping, the smaller tractor is far faster than the larger one, although a mower is even faster. Manuverability is the key to speed. For loader work, the smaller machine gets into places that the larger cannot get into so its manuverability makes up for its lower capacity.
In the 30hp class of machines you can run a wide range of sizes, from the small B7800/B2910/B3030 class tractors up to the largest of the group being the L3130, CK30, 2910 (Branson), or you can shoot the middle size & weight range and look at the JD790 & 4x10 classes, New Holland TC29, Kubota L2800HST etc.
Your jobs sound like they are mostly mowing, tilling, cutting. Those jobs require PTO horsepower, the more the better. In my mind, those are also jobs for a light tractor to prevent soil compaction, rutting, etc. You want to work in woods, if you want to knock them down, get a big tractor, if you want to make nice paths through them then don't go any bigger than you need.
I admit to believing a few things so let me show you my bias. Most of us buy bigger tractors than we need. Most of us are testosterone junkies and think bigger must be better. Most of us are wrong most of the time (just ask the lovely Mrs_Bob how often I am right /forums/images/graemlins/crazy.gif). My experience shows me that on a small property, I want small tractors with the most HP I can get for most of my tasks most of the time. You are considering a B7800 (you said so in another thread), and while I don't know if that is the lowest price tractor or not, I do know it is the smallest & lightest 30hp tractor on the market today, and there are probably at least 100 guys here on TBN who use a varient of that machine (B7800/B2910/B3030) and are amazed by the amount of work it can do and how efficient it is for every task from mowing the lawn to digging a trench. It gives up some capacities to bigger tractors, and it gives up some traction to heavier tractors, but your tasks don't dictate the need for eeking out the last ounce of traction the HP can use and the trade off is a benefit to you in terms of going easier of the turf and less compaction in the areas you will till.