Green apples, different kinds of bread, carrots and cauliflower, too. If you do a cheddar-based fondue, jalapeo bread is awesome. And chocolate dessert fondue is great with bite sized cheesecake, pound cake, strawberries and rice krispie treats. Yum!
The Gruyere gives an incredibly sweet and nutty flavor to the fondue, the sharp Cheddar makes it tangy, and the Emmentaler blends it all. Cooking the flour first helps the mixture not to be so pale and powdery.