Regardless, if there's any evidence at all that the DB is taken, assume the passwords are broken. Now where's the credible evidence the DB was taken?

UPDATE REGARDING LEAKED ACCOUNT INFORMATIONS

We will address this issue too and prevent logins from each users. Leaked information includes username, email and hashed password, which does not allow anyone to get to the actual password, should it be complex enough. If you used a simple password you will not be able to login on Mt.Gox until you change your password to something more secure. If you used the same password on different places, it is recommended to change it as soon as possible.