Not necessarily. There are many different ways to create currents in a tank. Powerheads on a alternating timer is one way to accoplish this, a wavemaker as you mentioned is another, the squid current switcher also works, and then there are a some sophisticated peices of equipment that work really well. There are many differnet approaches to current. It boils down to what your specific needs are and the amount of money you have to invest in it. The difference between a wavemaker and a powerhead is that a wavemaker sucks water in and then pushes it out all at one time causing the water to move from one side of the tank to the other. A powerhead just blows water in the same direction all the time.
There is one specific peice of equipment that I am particularly intersted in and its the Oceans Motions products. Heres a link:
Oceans Motions