This is a really stupid irritation, that can easily be fixed should Amazon choose to.
OK, so now, with the new joystick thing, the Kindle can selectively refresh parts of the display.
What this means is that only the central part of the screen refreshes (i.e. the bulk of the text you're reading) and NOT the very top and very bottom of the screen. That means that if you're in the middle of a book, and put the unit to sleep, the bottom of the screen reads: "Hold the power button to wake the Kindle up" (or something like that).
But that means that whenever I'm reading after I wake my Kindle up, I can read those EXACT words at the bottom of the screen, since the e-ink ghosting leaves those words there, and it NEVER refreshes. So the whole time I'm reading, I can still read the words at the bottom telling me how to wake my Kindle up.
AND, at the very top of the display, I can see the sliver of the screen-saver image! Stupid!
Anyway, this really bugs me, and I hope Amazon realize they need to refresh the whole screen when it comes out of sleep to eliminate this.