"Faith is that thing that allows you to believe in something that nobody in their right mind would believe if it wasn't for faith." - Archie Bunker
"No amount of belief establishes a fact." - James Randi
I prefer the more liberal definition of atheist. I withhold belief until there is proof. The more outlandish the hypothesis the more stringent the proof. If my wife says "I saw a grey and white cat when I went for the mail" I tend to believe her with no proof. If she says "I saw a purple and green cat" I think I would require at least an unphotoshopped picture. An invisible, all-powerful man in the sky? Show me the miracle.