We have a panini press and we l.o.v.e. it. These are some that we like in the panini press, but they'd probably work cold, too.
Greek pita, feta, onions, and tomatoes
Good crusty bread (we use nice dense italian ciabatta or some such), turkey, provolone, arugula, with basil pesto spread
Good bread, fresh basil, roma tomatoes, fresh mozzarella
(Cholesterol bomb ahead) Good bread, scrambled egg, procuitto or bacon, and cheese of choice
Rye, ham, swiss, alouette or other herbed cheese spread, lettuce
Good bread, hummus, roasted red peppers, kalamata olives
Good bread, grilled chicken, sundried tomato basil spread, roasted garlic, lettuce
I have more, but those are some of the ones I have written down that were hits. Most of the time we experiment with what we have and when we like something we put a card in the recipe box. Hope that gets the creative juices flowing for you. Oh, and for some more spread ideas, think about chutneys, pestos, sauces (like hollandaise or bernaise, for example), aïoli, herbed butters, and pastes like hummus.