The official presidential statement on Leonard Nimoy's death does a great job of capturing what made Spock such an important character:
Long before being nerdy was cool, there was Leonard Nimoy. Leonard was a lifelong lover of the arts and humanities, a supporter of the sciences, generous with his talent and his time. And of course, Leonard was Spock. Cool, logical, big-eared and level-headed, the center of Star Trek's optimistic, inclusive vision of humanity's future.
I loved Spock.
In 2007, I had the chance to meet Leonard in person. It was only logical to greet him with the Vulcan salute, the universal sign for "Live long and prosper." And after 83 years on this planet - and on his visits to many others - it's clear Leonard Nimoy did just that. Michelle and I join his family, friends, and countless fans who miss him so dearly today.
Obama is sometimes analogized to Spock by his political adversaries, but I've made the case in the past that his Spock-like qualities are a source of sound leadership. He's also by all accounts a genuine fan of the series.