My hubby and I share an account. This way we can share all of the books even if we may not want to read all of them.
I have also de-DRM'd our *.azw books so that I could also read them on the Nook Color. Depending on how many books you have in your library, it could take a few minutes to a few hours. I had around 500 books and it was a 12 hour task for me...