Note: Sales data from Wikipedia, which has links to the original articles with the results.
Starcraft II will have the same advantage that the Wii did by pulling in many adult gamers that spent hundreds and hundreds of hours playing the original game. I concede the point that the first person shooter Genre has always had a larger user base than the real time strategy genre but I still think that perhaps there could be a lot of demand for the RTS genre that has been marginalized in recent years as things have moved towards MMOs and the more modern FPS games. It will be interesting to see how it plays out and how blizzard is able to leverage their huge (paying) user base to market the this new release.
Maybe this will find success not through the older generation that remembers the original, but instead by giving rise to a new generation of RTS players who never even knew what they were missing in this FPS and MMO dominated world.