The music war started yesterday, when Rock Band was eventually released. Because of the new video game, Guitar Hero has practically lost its monopoly as the only major title giving players the chance to game on their favorite singers’ tracks.

Guitar Hero III: Legends of Rock brought in only in its first week on the market no less than $115 million. The game represents the first title of the series developed by Activision, although everybody knows that it was Harmonix Music Systems not Activision that created the popular Guitar Hero franchise. But, it seems that Harmonix couldn’t let go of the music world and developed Rock Band, which is expected to be the next big thing on the market.

Rock Band was released bundled with controllers shaped like guitar, drum set and microphone. The package costs $170 and it seems the price doesn’t represent a problem among the music-themed video games fans, as many retailers opened their stores’ doors at midnight so that the gamers could immediately grab the Rock Band package.

Rock Band represents the first act of MTV’s plan to spend more than $500 million on video games over the next two years as Viacom’s company expands beyond its TV base. The publisher’s traditional strong connection to the music world and the distribution power of Electronic Arts are expected to add serious support to Rock Band’s commercial success, although for fans Harmonix represents the most important part of this project. The Boston-based game studio “invented” Guitar Hero, which is a major hit even under Activision, so this new game it developed is expected to be even better.

Still, MTV helped a lot because it invested the necessary money in Harmonix’s idea: “For the first time ever we had the resources to really go for it," Alex Rigopulos, Harmonix’s head, said. "For us it's a dream game. It's really sort of everything we've ever dreamed of doing."

So, we shall just wait and see whether Rock Band will really be able to defeat its half brother, Guitar Hero III.