Peter Singer, Professor of Bioethics at Princeton University, is one of the most famous atheist in the world today. In my view he is by far the most consistent atheist out of all the famous Darwinian atheists (Dawkins, Hitchens, Harris, etc). He actually carries his evolutionary thinking to its logical conclusions. He famously has said things like: a pig is more valuable that a human baby & parents should be able to kill their children up to 28 weeks after birth. I find him to be the best representative of atheism. He does not try and incorporate theistic moralism into his atheism.
Dinesh D'Souza looks like he is about 15 years old but is sharp as a tack and one of the best debaters & writers on a Christian world view today. His excellent book "What's so great about Christianity" is a mandatory resource for anyone serious about defending their faith. I stumbled on these debates on the web & they are excellent. Below is the opening statement from D'Souza - the rest of the debate is on yourtube or here: http://ygod.web2.onlinenw.com/index.php?pr=Dinesh_vs_Singer#princeton