Of all the "software-defined" categories, software-defined networking is now garnering the lion's share of industry attention. A simple scan of industry publications and associated vendor positioning will amply demonstrate this.
A more tangible example was at the recent VMworld: VMware announced NSX, and demand for sessions was apparently 3x-5x oversubscribed. It seems that everyone wanted to go learn about the new capabilities -- even though VMworld is not a network event.
From my inevitable storage perspective, I couldn't be more excited about the potential. SDN concepts applied to storage and availability can potentially remake how we think about architecture, services and operations.
SInce I've never been shy in speculating about the future, let me share what I think we may be looking forward to down the road.