If you've been meaning to check out the Darksiders franchise, you couldn't pick a better time. For one thing, THQ could use the money. For another, it's really not that much money today. For the next two days, the PC download version of the "Franchise Pack" containing both Darksiders games, a Season Pass, and a ton of DLC, is just $13.19 on Amazon. The Saints Row: The Third "Full Package" with the game and DLC is just $12.49.
In non-THQ download deals, the Alice: Madness Returns Complete Collection, with both Alice games, is $11.99. In all three cases, these bundles are cheaper than buying the individual games! So even if you only want one Darksiders game, you should go ahead and buy the full set.