Angels are a pretty important part of my reef as well ... currently have a flame (that color is unmatched!) and a coral beauty (perpetual-motion-machine) in my tank, and they behave themselves pretty well. With fingers crossed, should be adding an Indonesian regal to my display for Christmas.
I'm partial to scribbled angels, but not going to go there in my little 220 - might try a watanabe pair. The Genicanthus (choose your favorite!) offer that cool dimorphism, and interesting finnage and patterns, but not much color - and they're probably just a bit smaller than your tang gang. Are you looking for more medium-sized fish, or are you looking to put an impressive focal point in your tank? I've seen a few reefs with emperors in 'em, and you could probably pull that off . . .
~Bruce, with fish ranging in size from azure damsels to quoy's parrotfish, and in shape from a regal angel to a zebra-bar dartgoby ... and only one tang