Image Viewer for e-Commerce Site

We like to add a robust, great-looking image viewer to our HTML e-commerce site. We are trying to move away from a Flash viewer, although want to provide as much interactivity as possible. We are open to ideas, i.e. doing a popup vs expanding the current image etc. Basically we like to show a larger image of our product. We have all the images / thumbnails ready, as well as additional image views (left, right, top, etc). Finally, there should be a image preloader always.