BlizzPlanet has a nice tidbit from Christie Golden about her upcoming novel about Arthas Menethil (better known as half of the Lich King, that bad guy we're going to be spending a lot of time with in the expansion). The book is due out next year (so odds are that we'll be approaching the end of the story by the time it hits store shelves), but it'll offer a look at the bad guy way before he started being bad -- the book starts with Arthas as a 10-year-old Prince, and covers everything between there to his little meltdown we witnessed in Warcraft III. The romance with Jaina is supposed to get some good coverage as well, so the book should be a good read.
And there are some bonuses for close readers as well -- we'll have seen some scenes before (including one between Arthas and Muradin in Beyond the Dark Portal), but of course, in this book, they'll be from Arthas' perspective. Arthas is undoubtedly the villian of the next ten levels in WoW (they even named the thing after him), but it's really exciting to have a villian with such an interesting and twisted past behind him.