This game solidified my love for Sarah Kerrigan. She is a straight out manipulative bad ass bitch in the Brood War campaigns, and really makes her Starcraft 2 iteration feel like a completely different character*. Not only that, but you get to see new Protoss heroes step up to the proverbial plate such as Artanis and Raszagal, all set to the turmoil of Protoss racism. Not to mention you have crazy humans from Earth, who are oddly all Russian, turn up in the Korpulu sector as well. Oh, and you get introduced to the mysterious 'Duran' who at first appears to be a UED agent, but then later defects to being Kerrigan's right hand man, and then mysteriously shows up on a planet trying to make a hybrid of the Zerg and Protoss races, telling Zeratul that he works for a higher power. All these tiny talking heads and sprites have way more characterization than half of the crap released as games today.
Then there is the pro gaming scene. You cannot mention Starcraft without pro gaming, as the terms are synonyms. Hell, South Korea's entire economy was saved because of the phenomena of pro level Starcraft play. Forget any other sport in South Korea, Starcraft sells out arena's constantly. There are even pro teams sponsored by the South Korean Military. That's right, a government is supporting pro video game play. There are what I like to call "dude-bro" gamers that think Call of Duty and Halo are professional gaming experiences and they do nothing but watch Major League Gaming** thinking that this is what pro gaming is all about. They have no clue. Halo and Call of Duty wish they had the pro gaming influence that Starcraft has.
Starcraft is my swan song to gaming. I will always have a copy in some way shape or form. Hell, Blizzard is practically giving the game away now that the game doesn't require a disc to be in the drive to be played. It will always have a place in my Zerg Infested Heart.
*Based on the small 33% of the story we have so far received.
**Not saying MLG is bad, they just have a long way to go compared to where pro gaming is over seas.