Hot on the heels of Guitar Hero: Aerosmith comes another Guitar Hero title, this time featuring Metallica. Scheduled for release in 2009, the details were uncovered in an SEC filing made by Activision.

While this bodes well for the series commercially, one can’t help but feel that this series is being milked to proportions that would make EA’s usual treatment of their franchises seem normal (NFS: ProStreet anyone?).

“In fiscal 2009, we plan to publish Guitar Hero: On Tour for the NDS; Guitar Hero: Aerosmith, Guitar Hero: Metallica, and Guitar Hero IV across multiple platforms,” the company said in the filing.

The charm of the Guitar Hero series was to play songs from bands you never even heard of rather than bask in the already popular tracks from well-known acts.

According to our sources (the voices in our head) Activision plan to release Guitar Hero: Madonna and Guitar Hero: Britney Spears as soon as possible.