I agree with Donnageddon. If you wait long enough, in fact, ereaders in general will become obsolete and you can buy the technology that replaces them.
I've had my Sony for about six weeks and I wish I had bought it sooner. In that amount of time, it has become a how-did-I-live-without-it item. Even if they come out with the SuperDuper version tomorrow for less than I paid, I'm better of with mine now.