If I had to pick one trout fly for anywhere in the country now, it would be an easy choice: the Muddler Minnow. This pattern (and its cousins) can be fished several ways, and it imitates a wide range of things trout love to eat. Greased up, it floats like a grasshopper. Stripped through deep pools, it looks like a juicy sculpin. Skated at night, it's a mouse. The more creative you are, the more you appreciate this classic.