The answer to the question could be (tongue in cheek)
Bono, but maybe you just think he's a singer and a talker whose glasses and mouth and audacity open doors and open minds.
Bill Gates - His money walks and talks and works. But he's really rich, so he must be really wicked. Plus he's a nerd.
Rick Warren - He's a preacher, but he talks about AIDS in church, so he can't be a good advocate for Christians to be engaged in meaty issues. Plus he wears Hawaiian shirts.
But a little guy you don't hear about much is Gary Haugen, whose organization called International Justice Mission is rescuing girls from sex slavery, attending hearings of genocide trials, and advocating for a gospel that engages the bloody mess.