Activision's latest in the Guitar Hero series -- Guitar Hero: On Tour -- has sold 300,000 copies in its first week of release in the US, putting it in the company's top five best-selling launch titles. Mike Griffith, president and CEO, Activision Publishing, was suitably gushy about the whole thing, saying "Guitar Hero is one of the most successful entertainment properties and continues to push the boundaries of innovation with Guitar Hero: On Tour."...