I decided to check out the Mass Effect novels; just finished the first one. Quite good. I really like this universe, I wish they'd do more with it. Maybe ME4 will wander a bit more and the tie-ins can, as well. I see some real potential for a book line like Gears of War or Halo to come off of this, not just this one fairly self-contained parallel storyline.
...though it is, of course, impossible (or at least rather pointless) to novelize the games, considering that their entire point is that you can make so many choices, so maybe that's a problem.