I was brought up in, and have now returned to, Suffolk.
Most local people I know would say that East Anglia includes the following:
All of Norfolk
All of Suffolk
North-East Essex. (i.e. Colchester is included but Chelmsford and Harlow definitely aren't).
Southern Cambridgeshire (i.e. Cambridge and Huntingdon are included but Peterborough and the Fens aren't -although we might just let Ely sneak in).
Some people might count in parts of Bedfordshire (i.e. from Bedford to the Cambridgeshire border).
A few people would also include southern parts of Lincolnshire, e.g. Spalding, Stamford & Boston, (but these are the 'traitors' who also try to include the dreary Fens within East Anglia).
I've heard TV reporters refer to parts of Buckinghamshire (e.g. Milton Keynes) and Northamptonshire (e.g. Wellingborough) as being in East Anglia but I know of no true East Anglian who would agree with this.
I've also heard TV journalists referring to both Oxford and Leicester as being in East Anglia but that's just plain silly!
Lastly, even admitting the apparent lunacy of certain journalists, I've never heard of anyone being daft enough to suggest that Berkshire could form part of East Anglia - well, not until I read your question anyway :-)
Chris