Steve - As I hope you know, I like and respect you a great deal. With that in mind, I have to ask you this:
Why is it that every time someone questions Christianity - or any other form of theism - you practically trip over yourself to define such theology as being the source of all that is Good?
Conversely, if someone does something evil, you rush to dismiss their Christianity as if the terms are mutually exclusive. A case in point would be Fred Phelps.
Fred Phelps IS a Christian. He believes his soul is saved through his belief in Christ. By definition - practical, according to Hoyle (and Merriam-Webster), biblical (John 3:16) and otherwise, he is a Christian. Yet, you have said he cannot possibly be a Christian because he is a wretched human being and the things he says/preaches are abhorrent.
Being a Christian does not make someone perfect (and nearly every Christian would agree with this, as the admittance and acceptance of imperfection is a key tenet to the faithful and proper adherence of Christianity). But I would assert that being a Christian also does not absolve people of being responsible for - and accountable to - their own actions.
I would argue that this responsibility and accountability aren't owed to an omnipotent/omniscient/omnipresent (yet completely - and oh-so-conveniently immeasurable/inaccessible/unaccountable/irresponsible) Creator/Overseer/Puppeteer, but to ourselves and our fellow inhabitants of this planet.
I would argue that Fred Phelps is both a Christian AND an abhorrent, wretched human being. There may or may not be a correlation between the two, but in his personal Venn diagram, he represents the overlapping area between the two spheres. This is NOT analogous to a matter/anti-matter interaction. The two can - and do - exist without canceling each other out.
We both agree that Good (and Evil) exist. Where we differ is where we choose to attribute the source. I would argue that one does not have to believe in "God" in order to recognize, appreciate, and do "Good," or to condemn "Evil." Why is Belief required in order to do Good and avoid Evil? Why should it?
If I said that all Good comes from the consumption of Mountain Dew and all Evil stems from invisible Oompa Loompas, you would disregard my words as being ludicrous, even if I could get several people to agree with me and write several stories about it, adding somewhat plausible and quasi-historical references to support the theory.
Even if I was 100% certain that I was right in believing this, you would think something wasn't quite right with my mind. Even if I could show you that drinking Mountain Dew made me more personable or more energetic or more intelligent, you would say there isn't quantifiable connection between the consumption of the Blessed Dew and its positive effects on my personality.
Even if I told you, "you just have to have faith that Mountain Dew is the Font of Goodness and the Source of Eternal Life," you would be justified in mocking me for being misguided at best (and a fool at worst).
How is this example ANY different?