One thought. If you buy the nook from B&N you still have a 14 day return option. You won't have that if you buy elsewhere. I think this is really important because you really need put the new update through it's paces and since you seem to not have been happy with several recent purchases (Kindle, 900, iPod Touch). Not trying to damper your enthusiasm but protect your pocketbook.
Good luck with the nook!