A pseudochromis would add a splash of color - the fridmani are nice.
Or you could get a sixline wrasse - they're always fun to watch as they poke around in the rocks.
If you're not planning on any shrimp, a flame hawk has great personality.
A yellow-tailed blue damsel would go with that group fine, and add a color you may not have.
If you're got some substrate, a watchman goby/pistol shrimp pair are fun to have.
Well, that about covers some of the easier fish. If you have a theme or idea on where you want to go with your tank, there might be some other selections commonly available.
Kevin