Currently reading Deliverance Lost, which is the 18th book in the Horus Heresy series. The Horus Heresy is an event which took place about 10.000 years before Warhammer 40000. Not exactly deep literature, but it's a rich universe, that has kept me hooked for a while. 54 books (or so) total, and been reading them in order since december. Some bolter porn can get a bit redundant, but the books and authors are varied enough to keep me invested. Most of them follow various Adeptus Astartes charactes (Space Marines, bio-engineered super warriors), with some supporting mortals, while others follow normal people, enhanced people, psykers (basically wizards), and a couple of the books so far have been short story collections. The scale of the series is immense, and sets the stage for the eventual 10.000 years of stagnation that led to the 41st millenium.
Also just finished The Last Chancers (set during the 41st millenium), which is a trilogy of novels, with a couple of short stories to bridge them together, centered around a character in a penal legion. Good stuff, though the ending of the final novel was a bit anticlamtic. Can't say much without spoiling the series, but penal legions are basically meat shields, but that's not the fate for (some) of the characters here.
Should probably get around to reading something other than WH40K related stuff (think the last thing I read before I started was Seveneves by Neal Stephenson*), but a bit too invested in the Horus Heresy, and at this pace I'll probably finish the series, and move on to the Siege of Terra during next year, I reckon.
*) Seveneves is basically about how to survive when the moon explodes in a fairly hard sci-fi setting. First part takes place during the preparation, second part takes place after the world has ended, and the final third part is set 5000 years later. The third part dragged for a bit, but enjoyed it overall. Can be kinda depressing at times.