13. Sheldon Cooper (The Big Bang Theory)
Sheldon Cooper isn’t the most conventional genius heartthrob, but Amy Farrah Fowler thinks he's tops. Who are we to disagree? And while decimal representations of pi beyond 40 digits aren't mathematically practical, he's probably the kind of guy who'll take that 3.1415926535... all the way out to 100 without breaking a sweat.
Jim Parsons stars as Sheldon in The Big Bang Theory on Thursdays at 8/7c.