Costello was the first man to "pop-song-ize" the ballad. You can argue that the Beatles did this, but it was only after Elvis Costello took the stage with the Attractions and set his spirit free. This man was an innovator, he was the first rockstar to popularize the Fender Jazzmaster, which is a guitar that has the utmost tonal control out of any guitar on the market. If you ever had the opportunity to see this man live in concert. you know the fervor he brought to the stage. Even in his old age (currently, he's dying of cancer, yet he is still touring) he plays his heart out every show,
Thom Yorke
Yorke wasn't just the man who revolutionized electronic-driven rock, he also revolutionized how we listen to our music to this day.
Yorke is a rockstar in the same sense that graffiti writers are artists. They're punk, driven, and built for the people. Yorke commands an emotional cloud over his audiences, yet he is outspoken about the rights of music owners and how music should be distributed. He was the first musician of all time to release a free album off of his label and was comfortable settling in court with the donated earnings he got from generous fans. In addition to that, Yorke brings immense amounts of passion to the stage whenever he steps on it, and when he steps off, it's back to activism.
Frank Zappa
People were enamored by this mustached fellow. Fans stared in awe every time he took the stage, he would reinvent another method of guitar playing, over and over and over, until the sound was uniquely his.