I'm a fan of the song 'You Know My Name' by Chris Cornell which was recorded for the Casino Royale soundtrack. I feel like this song matches very well with Dick's current situation and could even be a theme song for a tv show that revolves around this current era.
The first verse of the song begins with the lyrics, "If you take a life, do you know what you'd give" showing how Dick is in a position were might- and must- break from the ethics Bruce instilled in him. The verse refers to merciless eyes that have been decieved (the friends and family who think Dick is dead). The second verse speaks of "Angels who have fallen from blinding heights". This could either mirror Dick's career as a circus acrobat or the darker turn his life has taken. And of course, "Arm yourself because no one else here will save you" captures the cut throat and dangerous world Dick is now trapped in. Chris Cornell himself has spoken about how the song represents Bond's own emotional immaturity during the film and I think that applies to Dick, even if the song wasn't written for him.
So what 'theme song' would you apply to Dick Grayson?