If your uses include cleaning out ditches, go ahead and bite the bullet and get one with 3 axis controls, tilt, angle and SWING. The swing will be oh so usefull to keep the tip of the blade centered with your tires or when moving snow, you can just swing it to the side and it will clear a path further to the side of your tractor(reverse pushing) so your tires will be on cleared surface.
Also get one with a bit of weight so it will dig rather than just skip along.
Go to Tractorhouse.com and look at all the models of blades available and get some ideas of prices and weights. One of the little lightweight 200# blades is not going to do much for you. To get one that will do some work, you will have to spend in the neighborhood of $1000+ for new but there is usually a lot of good blades for sale used (very lightly used at that) I have always liked the RHINO brand for their weight and function. You may need to have a few counterweights on the front of your tractor to hold it down if you get a good stout blade but a wimpy blade is pretty useless.