To be labeled rye wishkey in the U.S., it has to be made of at least 51% rye mash. Anything else isnot officially rye, but what people call things are a different matter. Most people don't know that there's a difference between Kentucky Bourbon whiskey and Tennessee whiskey. Certainly the flavor differnece isn't huge, but they are made differently.

Wild Turkey make one of the best straight ryes going. Beam's 8 Star is a good starter rye as it's a bit lighter than the Wild Turkey.

And just in case you're not sure - Jack Daniels and George Dickel are the only major distilleries who produce Tennessee whiskey. All others (Beam, Booker's, Knob Creek, Maker's Mark, Old Charter, and Wild Turkey) are Bourbon.