Try out a few Skim and a few surf style boards. Then figure out what type you want to ride. You are probably always going to have new riders on the boat so it never hurts to have a entry level surfboard on the boat. We sell CWB Rides, Broadcasts, Tsunamis, Cortez, and Ventures at
http://www.Boardstop.com all the time at the $299-349 entry level price. Getting one of those now will never go to waste. Once you figure out what type you want then buy yourself a highend Phase5, Inland Surfer, Shred Stixx or other top of the line brand for yourself. then keep the beginners on the original $299-349 board.
Beginners on a high end board tend to - Run in to the back of the boat and crush the nose of your board, or miss the handle and put a HUGE dent in your $700 highend surfer, drop it on the platform and crush the tail. I;ve seen it all and shop boards have paid the price. So from experience I always let them ride a 'wakeboard' style construction board until they get the basics down and learn how to take care of pro level equipment.