My DSS is 16, and liked the thrill rides. Rockn'Roller Coaster, Tower of Terror, etc. I'm not a big thrill ride fan (I'm 20) and I really liked POTC, Splash Mountain and the likes. Make sure he rides Everest though! Roller coasters scare the crap out of me, but I loved Everest!
Before we went on out trip, my mom hauled out the Disney DVD's and books, and got myself, DSS and DB to pick our three top choices for each park. It helped mom figure out what we were interested in and it also helped with scheduling.