In the mean time, Talk Talk advise their customers that there is "no need" to change their passwords: http://www.bbc.co.uk/news/technology-38223805
Now, technically if they don't use the admin password they are probably OK. But (A) most people don't change their password. Heck, I work in IT Security and I still have admin passwords on some of my devices! (B) It's always good practice to change passwords ... just in case.
Granted, it's difficult to say how much better other ISPs are. But come on.
[0] http://www.theregister.co.uk/2016/11/15/talktalk_h1_fy2017_r...