Nook Color and love it! I chose Nook over Kindle because I read a lot and download the majority of my books from the library. If you live in MA, you can get a free Boston Public Library card and dowload books from them - the selection is incredible and I read pretty much everything I want.
My fiance has both and likes the Nook Color much better - he says it's easier on his eyes. We bought my dad one for a combo birthday and Father's Day and he is beyond thrilled. He said it was the best gift ever!