I grew up using—or rather, trying to use—an apple slicer that had such dull blades you nearly bruised your palms trying to push it through the fruit. There are still many slicers like that on the market, but the Williams-Sonoma Dial-a-Slice Apple Divider is a vast improvement. It requires some effort, but it has comfortable handles and can cut through even firm-fleshed varieties like Granny Smiths. You can adjust the blade setting to make eight or 16 slices, and the wide, serrated corer does a good job of removing the apple's middle.
Whether you buy this fancy gadget or just slice your apples the old-fashioned way, you'll find plenty of apple inspiration in the recently published Rustic Fruit Desserts (Ten Speed Press, 2009), by Cory Schreiber and Julie Richardson. It's a wonderful collection of buckles, crumbles, pandowdies, and more, with some very creative fruit combinations.