Michio Kaku – theoretical physicist at NYU who regularly uses Star Trek to illustrate his lectures. Hosts two weekly radio programs (http://www.mkaku.org/radio/)

Seth Shostak – the man gets paid to look for aliens, for gosh sakes. Also hosts a weekly radio program (http://radio.seti.org/)

And though he doesn’t strike me as particularly nerdy, Richard Dawkins’ surely gets an honorable mention for being married to former Time Lord Lalla Ward who portrayed the second incarnation of Doctor Who’s Romana – and was even briefly married to Tom Baker before hooking up with Dawkins. (http://richarddawkins.net/)