I rarely do. Maybe I am alone on this.
The same applies to hyperlinks within emails too.
Obviously, if the email is from a collaborator and the attachment concerns their latest results then I do open the attachment and read it carefully.
However, emails from administrators, conference and seminar organisers, and other random matters are only read if the subject looks important.
The main message needs to be in the body of the text otherwise it just does not get my attention.
What about you?