Joan Jett was a rock icon of the late 70's and early 80's, and her style is still influential today. Ask anyone who likes the rocker chick look, and they are most likely inspired by Joan's tomboyish-but-sexy rocker look.
I recently visited Seattle, and while there, I snapped this photo at the EMP Museum - it's the actual outfit she wore on the cover of the "I Love Rock N' Roll" album. It's made up of pieces that you could easily wear today, for Halloween or anytime.