I looked at the kindle since I've installed the app on my smartphone, but the more I studied on it, the more I leaned toward the nook color.
Finally bought a nook color and love the thing. Screen does wash out a bit in bright sunlight, but it's still readable.
Rooted it with Gingerbread via the microSD card so now I my Angry Birds sitting right next to the nook app AND the Kindle app! I just love the irony in that...
Plus, by rooting via the microSD card, I can revert back to stock simply by shutting it down and removing the card.