The single best piece of equipment in my kitchen is a digital kitchen scale from Will Knott Scales, the Salter 6055 . Although my scale has a handy storage spot, it rarely leaves the countertop. I use it dozens of times every day. With a little bit of practice, and recipes that are written with weights as well as volume measurements, you can nearly eliminate the use of measuring cups.
Although there are times when only a wooden spoon will do the task at hand, for most tasks that require a rigid spoon, a Tovolo silicone spoons is a an even better tool because it is heat resistant and non-stick. The spoon's handle is perfectly rigid, and that stiffness extends beneath the silicone layer of the bowl as well.
It's hard to beat the pungent spiciness of freshly ground pepper, and this 4" clear acrylic pepper grinder by William Bounds is a favorite. With a twist of the top, you can choose from three levels of grind. The whimsical fine print along the top ring reads, "made on the third planet from the sun."
Next to the digital scale, my digital thermometer has made perhaps the biggest difference in my cooking and baking. I use mine to test the temperature of ingredients, the gauge the internal crumb of bread, and check the done-ness of meat or poultry. The high-end thermapen is probably wonderful, but for a fraction of the price, I've loved this one: CDN Q2-450.
The Silpat baking mat is designed to line a baking sheet so that baked goods brown evenly and release easily. But the mats are also useful for lining a counter when you have to roll out dough or form loaves of bread.
My knife skills are mediocre at best, but with this Henckels 4 Star Santoku knife, I feel like an old hand at the cutting board. It's reasonably priced, well balanced, and a versatile size for most cutting and chopping jobs. I love the way it dices garlic and chops herbs.
Silicone muffin cups are wonderfully handy to have in the kitchen. You can fill them with batter and set them on a cookie sheet to bake. They make un-molding even the trickiest muffin or cupcake a fairly easy task. Because they are flexible, you can just push the muffin from the bottom. The cups are useful when a recipe makes a generous amount of batter and you need a couple of extra of cups beyond the 6 or 12 in your muffin pan. Additionally, when I'm baking a cake, I've often reserved some of the batter and baked a single cupcake for tasting purposes.
My Microplane brand grater/zester is a tool I use nearly every day, especially to zest citrus, grind nutmeg, and grate Parmesan cheese. The hundreds of tiny blades are razor-sharp, making quick work of grating tasks.
When I ordered an electric coffee grinder to use for grinding spices, it seemed like such a guilty indulgence. But I've ended up using it quite a bit, and love the time that it saves and the wonderful taste of freshly ground spices in the recipes I prepare. I use it most often for ground cloves and allspice, but it also grinds up dried vanilla pods (which I use in making vanilla ice cream - it really saves money over using just the seeds.)
Once you begin baking from recipes that list ingredients by weight rather than volume (those in many bread books, for example, or European recipes) you will eventually wish that you could measure in smaller amounts than your everyday scale can reliably deliver. That's when an Escali pocket scale is useful. When I reduced a bread recipe recently, this scale helped me measure the correct amount of yeast and salt.
I'd love to hear about your favorite kitchen tools - let me know in the comments.