I recently purchased some epub books from B&N to read. Well actually because of B&N geo restrictions, I had to ask my brother in the US to purchase them using my account (and NZ credit card) and once they were purchased I was able to download them.
Anyway I have found that the ebook selection on B&N and Amazon do not intersect completely and there are books on B&N in epub format that are only available on Amazon in hard copy. Plus of course Amazon do not make all their Kindle titles available to overseas purchasers.
I have found it's relatively easy to remove the DRM from B&N books (it's not stealing since you do need to know the credit card number used to purchase the book and the full B&N account name) and convert the epub format to mobi format to read on a Kindle, retaining all formatting.
The upshot of this is, with a Kindle reader and some knowledge, you can purchase books from both B&N and Amazon and significantly increase the library of books you have access to.
Information for those who have Kindles and are finding some titles they cannot purchase and are on B&N (and of course with a friend with a US IP address that they are willing to share account information with or perhaps know of a way to use a anon proxy server to present a US IP address).