Although I do like yellow tangs, they are at best an average fish not a center piece, that's why everyone has one. I also have a 120 with a male blue jaw trigger and a powder brown tang and I would consider neither a show piece. My tank is a fowlr so I don't have to worry about reef safe fish although my blue jaw was in a reef before I broke it down. There are some angels that are reef safe with caution, I am currently researching/ looking for a scribbled angel but would also consider a nice red sea desjardini tang. Look at some of the threads about pairs of fish. There are certain species of butterflies that can be paired together and make for an interesting interaction. I chose not to get the female blue jaw because of it's lack of color and wanted to save the room for something nicer but my male has a great personality, always follows me around the tank and feeds out of my hand.