I wouldnt move to the valleys
If you are from the valleys I think they can be lovely places to live (at least some areas). I have worked in the valleys and personally I loved working there, I have worked across a lot of south wales and the valleys was my favourite place to work.
There is often a strong community spirit and the people are really friendly. However there is no denying there is massive poverty, and I don't think I would move there straight off the bat. I think you'd have to chose really carefully and be confident you wanted to live in the valleys If that makes sense?
I wouldnt move to Newport either, I much prefer the valleys to Newport tbh. Really wouldn't move to Newport. Again there are nicer parts but to me the general town feels really run down, lots of drug use etc.
I agree abergavenny, crickhowell, Monmouth are lovely and safe bets. Caerphilly as well. Penarth is lovely but expensive. I like Barry but again it can be quite run down in places.
Some people have mentioned llantwitt but I think llantwitt has quite an isolated feel.
I agree with the poster who suggested the cwmbran area