I didn't like mushrooms when I was younger and although I am a commited Carnivore (that's right I capitalized it), I have been known to use them as a meat substitute. The shitakes that come with the scallops at L and N are awesome. But frankly my favorite mushroom dish is one I make. Cooking mushrooms takes some practice, but they are cheap so read up and experiment. I like to quarter white mushrooms and sauteed them over medium low heat in melted and foaming butter, a pinch of kosher salt and fresh cracked black pepper. When the shrooms have absorbed the butter add a couple dashes of Champagne vinegar and optionally 1/2 teaspoon of coarse ground dijon mustard.
Yummy! Try it over steak or a nice piece of seared fish.