I wonder why people think good works should get them into heaven when they probably wouldn't want their bad works to keep them out. You talk about obviously bad behavior like murdering and raping but God is a completely HOLY and RIGHTEOUS God. Our righteousness compared to Him is likened to filthy rags! IF you don't believe in God and are placing your bet that He doesn't exist then you better understand the nature of Him in case you are wrong.
Thinking a sin is as bad as doing it. A man looking at a woman with lust is just as if he threw her down and had his way with her right then and there. Unforgiveness is a sin, in fact the bible says if you stand before God asking for forgiveness while you yourself hold unforgiveness in your heart...God can't forgive you! If you are going to be honest with yourself, your good acts are not going to outweigh what God considers sin. I don't care if you feed a billion hungry children, God said if you have unforgiveness PERIOD in your heart, he can't forgive you. The OT was lived out and passed down to us to show the need for a Savior and to show that no matter how hard we try we cannot be good enough. When you compare the holiness of God to our good works they are nothing.
Being basically good is not good enough. However, when you embrace the passionate act of Christ which paid the debt for our sin that we alone can never pay. You're good works are accounted to you as righteousness and the sin you cannot avoid is covered by his blood.
And personally, I think that living my life thinking "Have I done enough good today? Will it be good enough for God that I helped that old lady with her groceries even though earlier I cursed out the cashier? Does it even count since I sinned earlier? How much good is good enough? Will God notice that put an extra $5 in the offering even though yesterday I gossiped about so and so??"
And furthermore if you don't believe in God it's because you rejected him. And YES I am a mother but if my child said she hated me, and wanted nothing to do with me, how would I as a loving parent force her kicking and screaming to stay under my roof against her will. People who reject God make a choice and it doesn't matter what excuse they have, because as I said in another thread "An atheist who can't find God is like a thief who can't find a policeman."
That thief can say all they want that they looked long and hard, they can say they DID see a policeman but are convinced he was a hallucination... but the truth is, they don't want to find a policeman because they don't want to pay the consequence for their actions.
Bottom line: Stop asking a hypothetical question about saving the entire world from cancer. Be realistic with your own life. Get out the bible, write down everything God considers a sin. A sin is a sin there is no big or small sin according to God (whether you agree with that or not, if you are going to consider his existence and ask questions about hell, then you are dealing with the God of the bible and that's what the bible says). Now take a day to write down every sin you committed, and everything you consider good...and a good act no matter how good is equal to another good act. Tally it up. I guarantee it won't be good enough.
Oh and don't forget to forgive everyone who has done you wrong cuz no amount of good on your list will matter otherwise.