I use my reader (sony 505) for novels, main improvements I would upgrade for would be:
1. larger screen about 7" I think would be perfect
2. speed instant page refreshes would be a big attraction
3. ergonomics, easy to hold without hitting buttons by accident, but still easy to hit something to change the page.
4. font and line-spacing adjustable , my niece has dyslexia and this would be a big help to her.
I don't need or want a backlight, touch screen (that diminishes the readability of the screen)
I don't really want to pay for but would take at minimal cost:
wifi , which would be nice with a stanza like ability to download books
I'm not going to upgrade to anything costing more than $200