What better time of year to address the state of the Kindle than in the wake of the President’s State of the Union address? Amazon recently announced their earnings report for the fourth quarter of 2009, and the results were overwhelmingly positive. Is that success sustainable?

According to their statements, fourth-quarter profits were up 71 percent over this period last year. While much of that growth comes as a result of Amazon’s aggressive retail practices, it’s hard to overlook the influence that the Kindle has had on their bottom line. They have reported six Kindle books sold for every 10 print books during that period, indicating that the content attach rate is starting to work its way up to a critical mass. What’s more, gadget blog TechCrunch is citing a source close to Amazon that pegs the current number of Kindle’s sold worldwide at 3 million, as of December. Not a bad number when you consider they were only expected to sell 2.5 million by the end of 2010!

But while the state of the Kindle is stronger than it has ever been, the announcement of Apple’s iPad on Wednesday is a reminder that the e-Reader market is a constantly changing beast, and the current state of affairs should not be taken for granted. Of course, this is not an Apple blog, so if you want a full rundown on all that the iPad has to offer, check out Gizmodo or any one of the myriad of sites that have full coverage.

The aspect of the iPad that does interest me is, of course, the iBooks application that represents Apple’s first foray into the word of eBooks. Their presentation was slick, as has become customary for Apple, but I’m as dubious about the prospect of reading books on the device as I was when it was still being referred to as the iSlate. Reading on a backlit device with extremely limited battery power and no defense against glare just does not sound like an attractive prospect to me, touch screen or no.

Whether the device is ideal for reading eBooks doesn’t seem to have fazed the publishers who have already signed on to publish books on the platform. Apple is much more flexible with their pricing structure, and early indications peg their normal price point between $12.99 and $14.99, a not insignificant jump up from Amazon’s $9.99 standard. We’ve reported in past months how unhappy publishers are with Amazon’s discount model, and it appears that Apple is positioning themselves as a competitive outlet for those frustrations. The New York Times is even reporting that Amazon has pulled all books by Macmillan, one of the publishers who have officially thrown their lot in with Apple, from their site over these pricing disputes. Could it be the beginning of a trend?

Strong consumer enthusiasm for the Kindle is going to be their biggest buffer against the impending iBooks threat. Even if they’re unhappy with their chunk of the profits, it’s going to be difficult for more publishers to turn their backs on 3 million dedicated literophiles who snap up books at a much greater rate than the general population. What’s more, an increase in competition historically has downward pressure on the price of goods, so I highly doubt Apple’s effort to assuage publishers is going to influence Amazon’s pricing structure in a significant way.

The state of the Kindle is strong. We can never be totally sure what the future holds (though we do have an idea), but it seems as good a time as any to be Kindle owner. Why not jump on the bandwagon?