Electronic books are one of those gadget categories that always seemed to work better in sci-fi movies than in real life. But that may finally be about to change. Building on some less than compelling models that debuted earlier in the decade, the e-book market is now largely a two-horse race between Sony’s Reader line and Amazon’s Kindle. The Sony products look slicker (no keyboards) and offer expandable memory and more flexible file support (PDFs, text files, and so forth). The most recent model, the PRS-700, also has a touch screen and backlight, neither of which are available on the Kindle. But the Kindle 2 offers an improved design over the original, and it has built-in free cellular wireless that allows users to buy books directly from Amazon’s massive online store (Sony’s model of downloading to a PC and then syncing looks ancient by comparison). These are evolutionary products, to be sure–neither company’s product has yet to catch on with iPod-like popularity in the mass market–but one of these could well be the precursor to an eventual breakout hit.