Live brine/mysis shrimp have to be about as good as it gets for most species of fish.
In terms of frozen food, SF brand frozen brine shrimp followed by mysis seem to be the ones I'm having the best luck with along with the trusty beef heart brick. Another good one are the frozen dwarf angel meals, which my crew has learned to devour along with my dwarf angels.
I've had moderate luck with ZooPlankton, but not as good as many of the frozen foods. My bunch will spit out Prime-Reef. Too good for them I guess, or they saw the price tag on the pack and then decided to be fincky about it. They like 'fast food'.
I've never had any luck with any dry food for marine with the exception of the premium and better freeze dried frozen brine shimp foods like SF's, which I strongly recommend. My fish won't even look at flake, but they'll pursue the freeze dried brine shrimp provided I don't make it a constant menu item.
I feed a variety at mealtime by shaving off slices of variuos frozen foods with a razor blade, and dumping it into my back filter. Seems to work better and induces more ravenous feeding than one food at a time.