Tractors come in many different flavors and as has been noted, one size does not fit all. One point of differentiation is the 3-pt hitch that is found in utility/farm tractors. The 3pt hitch allows you to mount impliments like box scrapers/rippers and blades in the back. The 3pt is usually accompanied by a PTO (power take off) that allows you to power things like mowers, roto tillers, cement mixers, generators, water pumps, post hole augers, and chipper/shredders all powered by the tractors engine. In a way, a tractor can be like a black hole because there is always one more implement to buy.
The front loader is the most basic implement and it can sure be a back saver. There are also many ways to extend the usefullness of the front loader like pallet forks and hay bale spears. One thing to be aware of is that the weight ahead of the axel needs to be counterbalanced. There are weights specially made to attach to the tractor for balance. Many people though save money by filling the rear tires with calcium chloride water. If you are shipping one it may be worthwhile draining the tire prior to shipping and refilling it when it arrives.
One especially useful (to me) tool is a back hoe. My tractor is an older John Deere model 955 with a model 7 back hoe. The John Deere has a hydraulic PTO as well as a mechanical 540 rpm PTO. Tractors without the hydraulic PTO have to use a mechanical PTO driven hydraulic pump to provide juice to the back hoe actuators. Since the back hoe was built for the tractor, it is easily removed when I want to use the mower, for instance. I can mount/dismount the back hoe in about 15 minutes.
You can find tractors with as little as 20hp but some of the high power implements will not be usable. If you are looking for a small, cheap, low power tug you might consider what some farmers have done. Look into a ATV. One other thing to be aware of is that John Deere has different dealer networks for each division. A bull dozer (crawler) is construction equipment (I call them yellow Deere for their paint color) and a utility tractor is farm equipment (green Deere). I own both types and I can tell you it is a pain having to go to different dealers for consumables and spare parts. Fortunately the engine used in my crawler was also used in a regular tractor so I can buy things like filters from my farm dealer which is closer.
One web site worth visiting if you are new to tractors is:
http://www.tractorbynet.com/forums/
Larry
