I don't have a single favorite, but I recommend Ta Nehisi Coates, whose blog shows the good effects of working to be rational about hard emotional issues, in particular, those around race. Lately, he's been observing Confederate History Month by working on dealing with having a painful historical past.
It hadn't occurred to me that he was a rationalist, but it's true; so much of his blog is secretly about how to debate well.
Light reading about 'Rationalist Heroes'.
I am not sure how useful people find having personal heroes. I would argue that they are definitely useful for children. Perhaps I haven't really grown up enough yet (growing up without a father possibly contributed), but I like to have some people in my head I label as "I wonder what would X think about this". Many times they've set me straight through their ideas. Other times I've had to reprimand them, though unfortunately they never get the memo.
One living example is Charlie Munger.
He was an early practical adopter of the cognitive biases framework, and moreover he clearly put it into context of "something to protect":
"not understanding human misjudgment was reducing my ability to help everything I loved"
(The quote is from his talk on "Misjudgment" which is worth reading on its own http://vinvesting.com/docs/munger/human_misjudgement.html)
One interesting point is that Charlie is seemingly a Christian. I have a deep suspicion that he believes that religion is valuable, for the time, as a payload delivering mechanism.
“Economic systems work better when there’s an extreme reliability ethos. And the traditional way to get a reliability ethos, at least in past generations in America, was through religion. The religions instilled guilt. … And this guilt, derived from religion, has been a huge driver of a reliability ethos, which has been very helpful to economic outcomes for man.”
Also, judge for yourself from his recommended reading list - looks like something out of an Atheist's Bookshelf.