Well the greatest acting performance and the best performance in the last five years is John Middleton playing Ashley Thomas with Dementia. If he dont win an award for this storyline then there is something seriously wrong

Steve Mcfadden - Phil Eastenders
John Middleton - Ashley ED

Tina O'brien & Jack P Shepherd - David & Sarah Platt
The guy who plays Nick Tilsley

To add I think that the characters supporting Ashley in his syoryline have also been fantastic

Edit. The guy who played Paul Coker, the episode he appeared dead in the coffin was the actors best performance in the role