I have had my nook since September, and absolutely love it. Wish I had waited for color one, but I use it everyday, as does my oldest daughter.
Besides all the free books at bn.com, I can buy books from other online sources, like my employer. I need to sideload them and they are stored in my documents, rather than my main shelf/library, but that's ok. If borrowing from the library is something important and you're considering the kindle, check out the message boards and see if there is a workaround.
For immediate ease of use, straight out of the box, fitting all needs of e-reader, email, music,etc., I'd pick the ipad.