If there is one tool that I believe belongs in every cooks kitchen, it's this: the Microplane.
Whether it is to grind garlic into a fine mince, grate nutmeg into your apple pie or even grate parmesan cheese over pasta, it is the simplest tool, but one of the most useful. I for one love to cook with lots of garlic, but hate the process of mincing it, or putting it in a garlic press only to find half of it stuck in the bottom of the press. This takes all of that effort out of it and allows you to shred the ingredient right over your pan.
Microplanes come in all shapes and sizes, but I personally like this 12" long one. I find it to be the perfect size for nutmeg, citrus and garlic. Some of the wider ones make more sense for someone who foresees themselves using it to grate cheese often. Go with whatever brand, price point and style fit your life best. If all else fails, head to your nearby hardware store and pick up a rasp!