I have a few different models:
1) A small, 5" tall triangular grater/zester
I bought from Marshalls for something like 5 bucks. It works great. One side has a slicer, one a small grater, and one a fine grater/zester. Works great for tableside parmesan or fresh nutmex etc.
2) Two different Microplane brand tools
. One is a fine grater and the other is a zester. We bought these because everyone used them. The sharpness is impecable, but I don't like how narrow the surfaces are. Many times I was rushing to grate cheese or something in the last minutes of cooking dinner and got cut. I never use those now, but I think the DW uses them once in a while.
3) A wider grater
. The surface on this is about 4" long by 3" wide compared to 1" wide on the Microplane brand. When the triangle is dirty or being used on another ingredient, I use the wider grater. It's fine enough for zest and coarse enough to make mounds of parmesan.
4) I also have this style zester
, which I barely use but it's pretty safe to operate.