Map:
ZE_PREDATOR_ULTIMATE_V2

Location:
http://www.gamebanana.com/maps/153717

Reason:
It is an epic escape map among the likes of LOTR. The map itself would challenge our players and see how well they can work together to survive. This is a difficult map and not one that we would likely beat anytime soon so the re-playability value is extremely high. Plus you fight a predator as a boss battle.