I have just went to borders to see the new PRS-600. The unit they have there has an awful display. It looked very washed out. I was really disappointed as I really like the idea of making annotations to my books and papers (I am a university teacher, when I read a paper I make many annotations on them).
Then, I was visiting engadget and came across a very interesting video on a new technology to add a pen to "any" screen
Note that this thing does not add an extra layer to the screen. Wouldn't it be nice to see an ebook reader with this technology (or something similar)? That would probably mean a thicker region on the top of the screen (to house the sensor), but I can live with that if I get the touchscreen with good image quality
Maybe Robert, from Astak, should take a look on this. He is well known for listening to forum members. Robert, are you listening?