Having been a “database” guy early in my career its one of the technical areas I try and stay on top of. In addition a solid knowledge of SQL has been valuable surprisingly often across lots of different projects.
In the last few years there has been the rise of the NoSQL movement seemingly changing the database landscape dramatically. I have read quite a bit and understand document databases to a certain extent though I really need to find the time to play with MapReduce or one of the others to help it sink in deeper.
I found this interview with one of the innovators in databases really interesting on a few fronts.
It helped set the context and value of NoSQL (though I want more!), it put the database industry in general in perspective from a business standpoint and lastly it provided a nice history.
It took me a few visits to get all the way through but it was worth the journey.