I chose my first ereader with great care and a lot of help from Mobileread.
All my reasons for choosing the original Nook 3G/Wifi are still valid.
That having been said....
The Kindle 3G may be my very favorite gadget ever. Pearl e-ink is crisp and clear. It is insanely fast and the internet browser is amazing! It is small and light and feels great in my hands. I didn't know that the 3G was everywhere, the Nook 3G only allowed me to go to the B&N store. I used it to add appointments to my Google calendar at the PT yesterday, awesome!!
(Yes, I know I can root the Nook and I did play with it that way for awhile but the battery drained too quickly for me)
I installed the jailbreak and put custom screensavers on which always makes me happy. (thanks so much Kindle devs!)
My one con so far is that the Kindle still looses when it comes to organizing my books. Collections are nice but I am kind of an order freak and I want them alphabetical.