I kinda like the lightness of the Kindle. I have dainty hands though

I read for looong periods of time—because once I start a story, I need to know what happens next—so holding up heavier books (ahem...Twilight and Harry Potter hardcovers) or e-readers can get tiresome.
The Nook Color is a bit heavier than the kindle, but I like the interface and the touch screen better. The touch screen causes the battery life to die quickly though.
I like the Kindle because I can read outside in the sun, and it looks more like the page of a book than a screen, which is easier on my eyes.
I just wish I could transfer my books from one to the other.