Best Icon:
2nd Joan Jet, ditto Elizabeth Taylor & Madonna, Diane Lane, Angela Bassett, Juliette Binoche, Chaka Khan, Salt n Pepa, last but not least would like to see an Asian Icon and I would nominate Michelle Yeoh (she was a bond girl and also in Memoirs of a Geisha. She is not only an actor but an accomplished martial artist/stunt woman)
This list is younger but I also like: Alicia Keys, Jody Foster (I know she's barely wears makeup but I think she's very unique), Kate Moss, Gisele Bundchen and the whole Kill Bill Icon cast
Worse Icon:
I can't really think of many but I would say someone that hasn't earned respect and admiration and that would be someone like Paris Hilton. I don't want to be a hater but she doesn't "do" anything other than get in the tabloids and has zero talent IMO.