The Dreamwidth risk is if your LJ account was among those in the data breech (which basically means 'did you have an account then') and also used the password on Dreamwidth or anywhere else.

(There's also a theoretical risk of people being able to connect accounts you had on LJ, even if the only connecting info was the email address or password - aka non-public info.)

I'm a little baffle by the unhashed password DB - when I was on the LJ Terms of Service team, back in 2003/04 they were hashed.