I may not be in movies, but I have acted in, directed, and written plays. I know decent acting, and she is a terrible actress. Nobody ever said you had to be talented to be successful in movies or music. In fact, there are tons of examples that show just the opposite. My idea of good acting is Dustin Hoffman, Edward Norton, Robert Downey Junior, etc. As for women, I would say Helena Bonham Carter, Maggie Smith, Scarlett Johansson.
And based on the interviews I've seen of her, and other times she has been on TV and was not acting, she is indeed dumb in real life. She does not seem capable of carrying on an intelligent conversation. Hell, I saw her on the Girls Next Door and she didn't even look smart next to the airheaded playboy chicks.
As for defining ditzy, I think she looks like the rusty gears in her head have grinded to a hault. I can't stand chicks who are constantly staring blankly into space with their mouths hanging open.
And no, I would not be all over her. Like I said, I would bang her. But I would never date someone who didn't stimulate me intelectually. There are way to many hot chicks out there for looks alone to hold my attention past the first nut or two.