Like the previous two posters have said, you should probably go with a color tablet. Borders and Amazon sell the cruz reader for 119.99, and the cruz tablet for 249.99. Here are links for the cruz readers.
http://www.borders.com/online/store/...ew_cruz-reader
http://www.borders.com/online/store/...ew_cruz-tablet. I know you said eight inches but I doubt you'll be able to find a reader that large for 420 or less.