Does a Christian need to be perfect?

There seems to be an odd binary logic taking place with many Christians in regards to their belief in Christianity. To wit, either you are (or worse...have always been) a perfect non-sinner, or you are a sinner. Isn't it kind-of like saying that only two percentages exist? O% or 100% ?? What about the middle ground. 55% percent or 21% for example or maybe 2.4% ?? In other word for example one teenager steals a candy bar. But another teenager robs a bank at gunpoint and steals 5 million dollars. Furthermore it will be a lifelong habit of the two different individuals. So overall it might be rated that the candy-bar thief is about a 3% on the evil scale but the bank robber is a 87% or so. How is it therefore that they both go to the same place in Hell and burn forever the same? Furthermore let us suppose that they both were baptized into a typical "grace will save you no matter what" kind of Church. And yet they still continued to do their "dastardly deeds" until their death. They did not repent not a single bit. Now they go to Heaven, but the people down the block who do the same thing but were not "saved by grace" will be burned forever. Does this not seem truly insane? What kind of God would do that? Does works have nothing to do with your station in the afterlife? Is God truly that cruel, that barbaric, that unjust to do that? Doesn't it stand to reason the more righteous you are as a person, the better will be your reward in the afterlife... be you Jew, or Hindu, or Born-Again, or whatever? If you are rotten according to your rottenness will you be rewarded. If you are righteous according to your righteousness will you be rewarded as well. Isn't this more logical then the binary approach favored by so many, that excludes the middle group (which is essentially everybody, just about)? And how is it that somebody like Stalin and Mao Tse Tong who murdered millions, if he was a fundie, would go to heaven, but the most pious saintly person like Gandhi, and Mother Teresa... will burn in hell just because he and she wasn't a fundie? ? Surely any rational person can see the falacy of this... eternal Injustice.