My JA Henckels set of knives.
Other than that, I have a lot of cool little tools I like, but they are not expensive or special things. I have had a Kitchen Aid stand up mixer for about 15 years; I hardly use it anymore, since I rarely bake. I also have a bread machine that my exchange student gave us for a present that whenever we use it, we say, "Why don't we use that more often?"