I'd say: Ron Paul's volunteers. Daniel McCarthy writes a nuanced and graceful essay on similar lines:
If the Republican Party is full of pretenders, where does one look for Goldwater's true heirs?
To answer that question, one has to look to the sharpest division that split the Goldwater movement of the '60s. It wasn't the division between libertarians and traditionalists, it was the division that separated idealistic libertarians and traditionalists alike, the campaign amateurs, from the campaign professionals. The conservative movement still pays lip service to economic liberty, social order, and military strengthbut on all three points, Republicans have become hollow men who have preserved the rites of Goldwaterism but who long ago lost its spirit. That was an amateur spirit - in both the best and worst senses of the word - and it drew together in common cause traditionalists and libertarians as different as Brent Bozell and Goldwater speechwriter Karl Hess.
...Today, nation-building and empire, together with K-Street politics, is about all that animates the Republicans who claim to be following in Goldwater's footsteps. They've lost what the 1960 and 1964 Goldwater movements were really all about, and they won't rediscover what they've lost by furrowing their brows wondering if Goldwaterism was really purely libertarian or fusionist. Goldwater himself was a man of the American West, and his legacy can be claimed by either libertarians or traditionalists - if they can put the principled spirit of the old movement before the emoluments of politics.