I find some of the responses by faith believers in this thread to be very interesting -- but of course, being perfectly honest, I must admit that I've always found the notion that it takes belief in God to be a "good person." Let me see if I can explain why.
Let's start with the case of slavery. Slavery is officially outlawed all over the world today (although there are still actually millions in bondage). But slavery was not abolished in Canada until the "Act Against Slavery" in 1793 (one of the earliest in the world), or the "Slavery Abolition Act" in the British Empire in 1833. In the U.S., states broke into civil war in 1861 partly in order to retain the institution of slavery, and Lincoln's "Emancipation Proclamation" (an executive order, subject to overturning in an ensuing administration) came only in 1865.
Now, I'm told that Christianity has been around since the early 2nd century CE. But for some reason, neither God, nor those who claimed to speak for God, could understand what we now know -- that slavery is a very bad thing -- for literally centuries. How is it possible -- if goodness requires God -- that this particular goodness took so bloody long?
Can it be possible (which is what I think) that God had -- in very real fact -- quite literally nothing to do with it. Doesn't it appear as if this is just we humans figuring out for ourselves that, because we would really hate it if somebody captured us and sold us to somebody else in perpetual slavery, that it must therefore be wrong to do it to anybody else?
It's similar with the Universal Declaration of Human Rights, by the UN in 1946, which basically resulted in most nations (not the U.S., alone in the Christian world) from banning capital punishment.
I maintain, therefore, what I always have -- that we do good when and because we want to, not because God wants us to, and when we want something badly enough, not even belief in God will forever stop us from doing whatever necessary to get it.