Destiny players who have been long time Bungie.net users could receive special Bungie or Halo themed rewards for their Guardians.
A few ideas:
A septagon emeblem, a blue fire for their helm, or a Ghost that looks like Guilty Spark.
-
Would be cool. Highly doubtful they can use anything referencing Halo without Microsoft's permission though. Though a Guilty Spark Ghost would be bad ass as exclusive content for the Xbox.