I'm going with AK Batman, and I'm incredibly eager to get him. I MAY be tempted by Batfleck down the road, but I'll probably rethink it depending on the sculpts. Either way, as far as these Arkham lines go? One Batman and a variety around him. There's just TOO MUCH AWESOME coming from Prime 1 in terms of the Bat family and rogues to not pick up more than just a variety of Batman.
If all goes well and I can swing it, I'll be in for AK Batman (already on PO), Arkham Knight EX (already on PO), Catwoman, Harley, Nightwing and Batgirl. That's if release schedules are okay, and I'm able to put the money needed aside. Prime 1 is turning out so much great stuff, which makes it tough because there are still some awesome Sideshow pieces on deck (Spider-Man on PO, Red Sonja, Masters of the Universe, Star Wars PFs incoming)...it's both good and bad to be collecting now!
Deathstroke is also really, really tempting. I'll have to think long and hard about it though, as these are huge investments (even bigger being from Canada!) and space will also be an issue. I'd go with the five mentioned above before picking up Deathstroke, but man does he ever look good! I try not to think of the dollar amount that all adds up to...it's too painful if you think like that.