Kevin is right, when planning on doing you own tuning, diamond stones are excellent for sharpening, however I would recommend a few things.
Do not use diamond stones without a proper side edge bevel guide -- with a clamp to hold the stone secure -- unless you are SKILLED with that tool and are able to make sure not to roll the edge over. That means using a diamond stone CAN result in screwing up the edge by removing the tip of the beveled edge which is known as "rolling the edge over" and is a mistake that is easier to do than you would think. Once rolled over the edge will not hold on hard snow, it can be fixed with a file, but the message is to be careful and use a guide if you are not sure you know what you are doing.
If you have a 2 degree side edge, which is fairly standard, use a 2 degree side edge bevel guide with the diamond stone secured by a clamp. If you have a 1 degree or 3 degree then use the same degree side edge bevel as your guide.
There are 4 basic types of stones available and here is a description of what each is best at when using them on your edges.
1) Oxide stone (pocket stone) used to remove burrs and/or rough polish (many grits available), yes you can use a $60 diamond stone, but removing burrs with a diamond wears the tool down, so I recommend removing burrs with a $5 oxide pocket stone.
2) Diamond Stones are used to sharpen (many grits available), competitors sometimes go from a 100-200 grit down to a 1000 grit.
3) Ceramic Stones are used to harden the edge after using files or diamond stones which soften the edge (many grits available)
4) Gummi Stones are used to "break the edge" which is removing the micro hang-burr that results from using any tool that cuts and softens the edge, such as a file or diamond stone
For selecting your set of tools, Race Place is an excellent choice as they design their own tools and are experts at recommending the tools you would need for any level of skill.