score:6
Deriving from the topics of Original Sin and Common Grace, I would argue that the answer is "both".
Let me expand. Our born nature is that of a sinner - one who cannot obtain God's favor on his own. However, we also have natural tendencies to take care of immediate family (Matthew 5:47 "If you greet only your brothers, what more are you doing than others? Do not even the Gentiles do the same?" and Luke 11:11 "Now suppose one of you fathers is asked by his son for a fish; he will not give him a snake instead of a fish, will he?").
In so far as it benefits US, we are "basically good". But since we tend to epitomize selfishness, when the benefits for US no longer exceed the cost, we will tend to be "basically evil".
As to the extreme examples of that (theft, murder, etc etc), the cost-benefit analysis was either never made, or is highly skewed.