If you don't need color, maybe you should get an eink reader.
Now, if you watch movies or browse Internet a lot, I believe the Nook Tablet is better than Kindle. However, I ended return it because I mainly buy from Amazon. Because I wanted a reader, not a multimedia device, I found no reason to buy a Nook Tablet if I am not going to use it as an ereader device anyway. The Nook Tablet is less open, but better hardware and more vivid colors than Kindle.
Now, I respect your comment about SD cards, but if you are going to buy from any regular online store like B&N or Amazon, you should not worry about that, as they all reside in the cloud.
You can still download and back 'em up via Calibre locally, on your PC at home, but as long as you have wifi or some connectivity, you can get any book any time, in seconds.
Last edited by jocampo; 03-05-2012 at 12:23 PM.