There's currently some talk that Battle.net might itself become a pay service, but as far as I know it's only talk. I've yet to hear anything about monthly fees for either StarCraft II or Diablo III.
Will SC2 be a good game? Well, I'd certainly hope so! Blizzard has yet to release a genuine turd (though there are some, myself included, who might count Warcraft III as their first real misfire)
Will SC2 be a good game? Well, I'd certainly hope so! Blizzard has yet to release a genuine turd (though there are some, myself included, who might count Warcraft III as their first real misfire)