Seems a good a place as any to express this point. A number of games have books and comics to dictate what happens in the universe of the game that may not be important enough, or is too expansive to include. I personally love this, as older game series left me wanting with the setting or the characters. Generally it could be said tabletops offered the gateway to this, as they're a gateway to modern gaming now.
Dungeons and dragons have hundreds of books, i'm sure, by over a dozen authors to flesh out the setting. I've been delving into a similar tabletop setting; Warhammer 40,000. There's at least a bakers dozen of authors pumping a staggering number of books out, but Dan Abnett seems to be setting the trend, his works of fiction changing for fleshing out the canon of the tabletop games themselves!
I wonder when enough is enough, and what books/comics you guys may have picked up for love of a game. I've picked up a gears of war book, a few halo books, debated with a few mass effect books (the story in game has enough to fill two novels worth alone) but there's a sort of advance on the tabletop games. Dan abnett has kept a particular character's story alive throughout 15 full novels, with little intent to stop now. Another six for a faction called Inquisitors, Three for a sort of 'history' for the current setup, two stand alone books, and the guy still does books for X-men, Dr. Who, star trek...it's mind boggling.
Gaunt's Ghosts- 15 books
Eisenhorn (inquisitor)- 3 books
Ravenor (Inquisitor)- 3 books
Titanicus (machine cult)- one huge ass book
Brothers of the snake (space marines)- one book
those are my current list, most are series