Have you played any of Skyrim's expansions yet? I'd wait for a sale, obviously, but Dragonborn looks bitchin'. I've played all the way through Dawnguard and loved it.

Hm. $15... I just did a haphazard glance at Amazon's selection for that amount. Looks like the GOTY edition of the previous two Batman Arkham games are on sale right now, which might fit the profile of what you've given us. (Digital download, too!) Hope that helps!

There are a ton of great PC deals on Amazon right now.

Scribblenauts unlimited - $7.50

Spec Ops: The Line/Bioshock/Bioshock 2 (this one especially might be great for you since you seem to like modern shooters) - $10 (seriously, one of the best deals imaginable)

Tantalizing THQ Bundle (Homefront/Red Faction 2&3/Stalker/Space Marine/Metro 2033) - $10

Darksiders Franchise Pack (Darksiders 1 & 2 and all DLC) - $13.19

Just Cause 2 - $3.74

Dark Souls - $15

Batman Pack (Arkham Asylam & Arkham City) - $10

PS3 Journey Collector's Edition (not quite a great match based on your likes, but 3 amazing games) - $30

After digging all those up, I remembered there was a thread over in r/gamedeals that covered the Amazon sales. I think the above are the best deals or major standouts, but check it out to see if anything else catches your eyes.