Allow cheeses and butter to stand at room temperature until soft.
Shred or cut Cheddar into small pieces and put into the large bowl of an electric mixer.
Add cream cheese, blue cheese, and butter; beat until blended.
Add garlic and beat until creamy.
Cover and chill cheese mixture for about 3 hours or until firm enough to shape into balls.
Divide in half and shape each half into a smooth ball; wrap airtight in clear plastic film, place in a plastic bag, and refrigerate or freeze until needed.
Allow frozen cheese balls to stand at room temperature, unwrapped, 3 or 4 hours before serving.
Sprinkle nuts on a piece of wax paper and roll each ball in about 1/3 cup of the nuts, pressing in lightly.
Serve with assorted crackers or wafers.