Its has been decided guys:
I have chosen Hive Fleet Krak... wait wrong topic
I have chosen the Mymaera craftworld purely based on aesthetics alone, shortly followed up by Biel-Tan and Iyanden.
Reasons why I did not choose biel tan: painting white at a consistent level
reasons why i did not chose iyanden: i want a flexible fluff army - not all ghost warriors

- though the new wraith stuff are cool.
Thanks again guys so much - I shall be doing a blog later on to show how I get on.