3:00 - FMV sequence in a spaceship - looks Terran - zooming in on a metal door - door opening - reveals a guy with a cigar in chains - prisoner - door shuts behind him - there's so much bass the room is shaking - guy steps into some kind of metallic devicce - legs are strapped in - guy rising toward ceiling - Korean text on screen got people very excited - another part of the machine is dropping metal arms on him - machine whirring - applying armor to his torso - extremly detailed visuals here - now guy is strapping on gloves - armor is molding together - seems like a Terran marine - rockets turn on - zerg now onscreen - Marine delivers a line - StarCraft 2 officially announced.
Blizzard North finishes Diablo 2 LoD
Blizzard Finishes SC:BW
Blizzard Finishes Warcraft 3
Blizzard announces WoW
Blizzard annouces SC:Ghost
Employees leave blizzard
Blizzard Finishes WoW
Blizzard indefinitely postpones ghost and another unannounced project, states that there is still another project in the works (SC2).
Now we can assume SC2 is being made by the Warcraft 3 team, former Blizzard north had a canceled project but is most likely working on something new unless they were absorbed into the World of Warcraft fold for the expansion, and then there is the Blizzard console division (formerly swinging ape studios who were doing ghost) who we can assume are working on a project as well.
There was no mention of Hero units in the blog update. It sounds like Blizzard opted to go with immense, unique late-game units rather than Heroes. This isn't too surprising since that was one of the things that SC zealots faulted WC3 for; the importance of your Heroes. Leveling them up, getting them items, keeping them alive, etc. Not to start a debate on that topic, I don't think it really matters.
Blizzard is obviously going to design SC2 to get every single person still playing SC to buy it. They can pretty much bank on everyone who played WC3 to buy it already, so those people still playing SC are the ones they have to really appeal to. They'll do that by maintaining the look and feel of SC faithfully and adding on to it. Which from the IGN blog descriptions, it sounds like that's exactly what they're doing.
Speculation about future Blizzard games other than SC2 should probably be kept in that other thread about the job posting.