Specifically, for each increment of three months with an active account, players will unlock valuable in-game “items” which will come in the form of costumes, powers, badges, and more! The program is retroactive by player account and rewards will be applicable to all characters within each respective account.

The jewel in the crown of the Veteran Rewards promotion appears to be something heroes and villains have been longing for; angelic and demonic wings.  Here is CoH's page on wings including a few pictures and a short video.