AFAIK Voltaire was clearly a Deist not an agnostic. Anybody want to debate this before I change it?
I'm not sure whether we should consider the logical positivist attitude that God talk is nonsense as a form of agnosticism. Perhaps it should just have it's own page, or be filed under atheism... I tend to see Ayer described as an atheist far more often than as an agnostic (in fact I'm not sure I've every read a philosophical work which referred to Ayer as an agnostic, but I've not done any research to confirm this).
This article says agnostics have 50% belief in the existance of god. Then atheist is defined as 0% belief in chance of god. So how would you classify a belief of 0.0001% belief in the existance of god, i.e., basically disbelief but willing to change opinion in light of overwhelming new evidence?