This is looking really good, I love me some sci fi and aliens. Keen for the story and another dive into the Arcade maps that come out.
Official Site: http://us.battle.net/sc2/en/legacy-of-the-void/
Lots of information and pretty pictures on the official site. Arkships, different multiplayer modes etc.
Also some multiplayer updates for each of the classes:
Thor self repair and Battlecruiser teleport!
Ravager looks pretty cool. Lurkers returning!
Stasis Ward looks like a fun mechanic.