I don't have a very large list of people who I consider to have influenced my life, but without a doubt Neil deGrasse Tyson is on that list.
Neil deGrasse Tyson (born October 5, 1958) is an American astrophysicist, science communicator, the Frederick P. Rose Director of the Hayden Planetarium at the Rose Center for Earth and Space, and a Research Associate in the Department of Astrophysics at the American Museum of Natural History. Since 2006 he has hosted the educational science television show NOVA scienceNOW on PBS, and has been a frequent guest on The Daily Show, The Colbert Report, and Jeopardy!
If you would like to know why I admire him so, merely do a youtube search of his speeches and interviews. This is the very first video I heard from him:
The guy knows how to speak to the general public about science and why it is important to our modern society. He's got me much more interested in space and the natural world. I hope he can do the same for you folk.