In Cincinnati, I like Boardwalk Hobbyshop. It's in the Oakley neighborhood on Delta Ave (Oakley Square). It's a great neighborhood place. In fact, it's the only local, independent place that I know of in Cincinnati.
It's right next to a great burger restaurant named "Zips." Down the street is a great place called, "The Wurst Bar." Both are great places, and both are worth checking out as long as you're going to the hobby shop. The Wurst bar was on the Food Network show, "Diners, Drive-ins, and Dives."
Scratch, Oakley Square. It's Mount Lookout Square.