Ignore 3D - it's a gimmick which is already on the way out.
Buy a set with a Freeview HD or Freesat HD tuner built in (this is not the same as 'Full HD' or 'HD ready') it means you'll get the Freeview or Freesat HD channels directly through your TV aerial or dish - they are stunning on a set of this size.
The TV will need to connect to your router (either with a cable or wirelessly) - any content you watch from the internet will add a huge amount to your broadband usage - make sure you have an 'unlimited' data cap.
BluRay and DVD will play on any set.
For me I'd buy Sony/Samsung or possibly LG - others may have different views.