I love my Kindle and this is awesome news. For all of you on the fence, here's why I recommend everyone buy a Kindle (haven't used a Nook, but I think most of these points apply):
1. You will read more.
2. The reading experience will be better than you think--there was a 1-2 day adjustment period for me. After that, I didn't even notice I wasn't reading paper and ink.
3. You can highlight and make notes in books that are actually usable. Remember post-its, bookmarks, notes in the margins? I loved to mark-up books, but never pulled them out again to reference what I wrote. Now I have all of my highlights in one place. I can even highlight a passage and share it on Twitter or Facebook (if you have 3G, then you can do this while sitting on the beach!)
4. I have all of my books with me via my phone. I just read Moneyball and wanted to share a quote with a friend. I was able to open up the Kindle app and presto, I'm able to share it with them.
5. I am more mobile (I have less stuff). Instead of buying books to collect them, I am buying them to consume them. Others may not have this problem, but I did.
5. Did I mention you will read more?! If you like reading and have ever set a goal to read more, please buy a Kindle. If a friend recommends a book to you during the day, you can download it while sitting in a comfy chair when you get home, and can be reading it seconds later.
Most of the arguments about whether or not to buy a Kindle center on the price. At $140, it is well worth it when you consider the additional amount of reading you will do. You will learn more, you will read more books, it will be worth it!