Three days after Amazon declared the third-generation Kindle the best-selling product in its history, Barnes & Noble has responded with a similar claim.  It seems the Nook line of devices now qualifies as Barnes & Noble’s all-time bestseller.

One small nuisance: like Amazon, Barnes & Noble chose not to share any specific sales figures, so don’t think we failed to repeat the number of Nooks that have found their way into consumers’ hands.  The company only said that almost 1 million "NOOKbooks" were sold on Christmas.

However, Barnes & Noble did add in a statement, "The new NOOKcolor Reader’s Tablet, introduced just eight weeks before Christmas, is the company’s number one selling gift of the holiday season.  Barnes & Noble also announced that it now sells more digital books than its large and growing physical book business on BN.com, the world’s second largest online bookstore."

Then the statement continued, "With its growth across device and NOOKbook sales over the critical holiday selling season, Barnes & Noble has successfully established itself as a leader in digital reading."

And indeed, the apparent success of the Nook Color is important for the company.  Some onlookers thought the device bore too much of a resemblance to the iPad, while the Kindle’s large mindshare posed another problem.

The trick at this point might be to see how both Nooks and Kindles fare when the iPad 2 comes out.