My favorite ones, and I do have my favorites, are as follows and are in no particular order:
The Zester: I saw the difference zest makes in cookie and scone recipes, and, ever since, have become a HUGE fan of the zester. Super simple to use and boy does it 'zest' lemons and oranges quickly! Sidenote: i'm a huge fan of the brand zyliss.
Rubber Spatulas (in a variety of sizes/shapes): Probably the single most important utensil in baking after measuring cups and spoons. I really don't know what I'd do without my rubber spatulas. I'm pretty certain I use at least one every time I bake anything. They are particularly useful in scraping the sides and bottoms of mixing bowls. Not to mention gathering the remains left in the mixing bowl. A true gem.