I've the Nook,B&W. It is fine and for reading color is not necessary unless you will look at books with color in them. I think where I miss the color is when looking at the library and book covers. I'm vary visually oriented and color is something that stands out, helping to separate one book from another. Wifi connectivity etc are not a problem, working smoothly enough. Reading is better than with words on paper. Less eye strain.
First let me say that I don't really own a Nook - I have the Nook reader loaded on my tablet PC. So that may disqualify my opinion! But I would say it depends on your reading habits; if you read books only the b&w would probably suffice. I subscribe to a couple of magazines via the reader, and so I like the color display for those...