Despite your views on God, having a solidified view of the world on what is good and what is wrong brings you far away from nihilism or agnosticism. It has been argued that Atheists tend to have higher moral standards as they rely on their own self preservation for their morals, never having the opportunity to abuse a scripture for their own wrong-doing. The prison population being the "proof" to this argument, stating that prisoners are unlikely to be atheists (a statistic likely skewed by the prison evangelism ministries). That aside, you could say that as long as you believe in something, so stubbornly, you are not a believer in doubt. The difference between the heart of an Atheist and the heart of an Agnostic is that the Agnostic has more doubt than faith, the Atheist more faith than doubt. Albeit, in belief of universal, non-relativistic truths, a monotheist would argue it's faith in the wrong thing, but I would argue it's better than Nihil.