I recommend a Micro plane Type Grater. They are razor sharp, with a Stainless Steel blade.
I keep two on hand:
The Zester Grater is for grating Parmesan, Lemon/Lime Zest, Coconut, Cinnamon, Nutmeg etc..
The Medium Ribbon Grater is for Chocolate, Mozzarella, Ginger etc... this one can grate in both directions.
They are easy clean and come with a plastic guard to protect the blades when not used.
The price point on the Micro plane Graters I purchased were around $13.00 over three years ago and they are still like brand new. I use them all the time.