Yes; powerheads in the main display will help in multiple aspects. They provide flow to simulate ocean currents, help keep detritus from building up in your rock, help distribute proper flow to prevent stagnant areas, help distribute water helping to maintain pH, are essential for most coral; however in a FO or FOWLR tank you might get away with not as much flow you will still need powerheads, etc etc the list goes on. Koralias and Maxi jets are two good brands to look into. The are relatively inexpensive and do the job just fine. Depending what size tank you have will depend what specific flow rating powerheads you will need.
The vortech MP powerheads would be your top of the line brand. They have multiple settings and are basically miniature wave makers in themselves; however at around $450 each the price tag usually turns most people away.