What's more, for Starcraft II your match history, achievements, and current campaign progress will also transfer because it's stored on the server. The same is now true for any PC Blizzard game released in the past 12 years, including Diablo 2 and the original Starcraft. The disc itself is just a convenient way to install the game I myself bought it and didn't even use it. What's more, you don't even need the install disc again, as you can download the entire game client off the site. Once your account is linked, you never need your key again. If you don't have a account yet, you will have to create one. Soon after you purchase Starcraft II, you will link your key to your account.
The answer is yes, you will be able to install Starcraft II on any future box you have.
