If I was buying my first reader I'd buy the Nook no question. From what I've seen it's the most innovative reader yet. It's 100% lustworthy. But I have a Sony 505 so it's hard for me to justify buying.
It's not really clear if the BN DRM will work with other ePub compat readers, but I don't think digital readers will ever gain traction until the DRM is transparent like it is now with music downloads. New readers are nice but kind of useless if you are locked into a single bookseller for content (not including pubic domain books, of course).