Rename nodes based on field
Had this question once, came along this Generating node title from node fields

In the reactions, there's a little gem in the comments: https://www.drupal.org/project/auto_entitylabel 
You can use Tokens and al kind of this stuff ;-). When your field is field_foobar then you'll have the tokens [field_foobar-formatted] and
[field_foobar-raw]