Guitar Hero has officially been put to sleep, or so says Kotaku. Activision felt the decline in interest was just too great to continue working on it. Personally, I'm not too surprised. Guitar Hero as a game was kind of following a sports game schedule. Release a new game every year with a different line up, slightly polished graphics, and call it a whole new game. Sure, they eventually added support for other instruments, but it was really too late.
However, for all the Rock Band fanboys, I wouldn't feel too overjoyed just yet. While the main competition is dead, the entire music genre of games seems to be dying. Honestly, there's just not too many innovative things you can do with a rhythm game. Also, they are really expensive for someone trying to get into it... Hell, that's the exact reason I've never bought Rock Band, I don't want to pay for the drums, bass and mic. And now isn't there keyboard? Sheesh. I was content enough with just the guitar.
Anyway, I suppose we'll just have to see how this all plays out.