The game has not been finalized yet, but so far it looks just like what you would expect a sequel to StarCraft to look like. See the screenshots at IGN.com.
Originally the announcement today was speculated to be a StarCraft MMORPG due to sightings of Blizzard’s job posting for positions related to next-gen MMO game development, but apparently it turned out to be unrelated. Maybe for future additions to World of Warcraft?
Anyway, whatever the case is, StarCraft 2 is coming; South Korea’s productivity to drop by 70% in the next 5 years.
UPDATE: The StarCraft 2 official website is up.