The HDPS-L1 (have we met before?) is an 80GB photo storage unit from Sony that serves as a central place to store your digital photos, with all the appropriate outputs so you can watch edge-of-your-seat slideshows for when Grandma visits. It's about half the size of the average DVD player, so while not portable in the strictest sense of the word, it shouldn't be too much of a problem to bring it to and fro—the neighbor's house, the in-laws, jury trials, etc.
Images are transferred to the HDPS-L1 either via the built-in USB port or you can plug in any of the many types of supported memory cards, including Sony's MemoryStick and the ever-present CompactFlash.
Look for the HDPS-L1 in Japan starting on October 27 for around $300.