Someone asked this question in the "Best Portable Player" thread, but I don't think there was any real answer from those in the know. So I figured I'd ask here, since that's at the top of my list of factors that will determine if it's worth the money or not. I know Li-Ion batteries last through many charge/discharge cycles, but on a device this expensive, I'd hate to hear that I'm S.O.L. if the battery decides not to hold a charge anymore. So what's the story? Would it be some kind of "send it in to us" deal? Would we be able to buy a replacement? Or does the Karma become a paperweight at that point?