Can you imagine a holiday season without Amazon's e-reader series? The Kindle celebrates its fifth birthday today -- a device that, since its debut, has added bigger screens, slimmer builds, and even some damn decent backlighting. Back at the start, Amazon's first hardware was just a little chunky, covered in buttons, and housed a 6-inch 800 x 600 e-ink display. However, the online bookseller went on to dominate the then-nascent e-reader market, with no shortage of rivals now wanting claim their own slice of the book-loving crowd. Five years goes pretty fast -- we just wonder how many still have their DRM-protected Mobipocket e-books to hand.