For me it's a toss up between Paul Verhoeven & Stephen Hawking. Verhoeven because with his PhD in Mathematics in Physics he's gone on to make some of the most entertaining films of the 20th century. Starship Troopers, Total Recall, RoboCop; awesome movies, I know lol. Hawking because after reading a brief history of time it inspired me to pursue astronomy and mathematics as my fields of study. What about you guys ?