George, some notes: "decision-maker", while retaining some of the juvenile charm (and the Great Oz paynoattentionness), lacks the punch, the elan, of "decider".
Some suggestions:
Decisioneer. I think this has a certain swashbuckle to it. I'd go with this if I were you. That is, until some internets guy decides to call you Error Flynn. Oops.
Decisionator. Maybe stepping on Arnold's toes, but hell, he's a puny governor.
Choice-O-Matic. NOW how much would you pay?
The Mad Chooser What Chooses at Midnight
The King of the Echo People
Or you could really wow those squares and shout "I am the Hoodoo Guru!"