This is a very good article by Niel that touches on two of the most fundemental doctrines of Christianity that I just can't agree with. The doctrine of "Original Sin" and the doctrine of "The Total Deprevity of Man". I find the Biblical justification and proof texts for these doctrines to be quite weak. Although Niel doesn't discuss the doctrines per se, he does touch on another reason I fully disagree with these doctrines... I find them to be an unhealthy way of looking at yourself and can be quite damaging towards certain people's self-perception... via We Are Not Broken - Godless in Dixie
In his book, "Not In God's Name", Rabbi Jonathan Sacks argues that religions (almost all religions) need to change their focus. Instead of focusing on converting as many people as possible to think and believe like they do, religion should rather shift their focus to finding ways to make this world a better place.