When Judgement happens the only real deciding factor of your destination is whether you have honestly accepted Christ as your personal lord and savior. Good deeds great things, and you are rewarded for them in Heaven, but they are not, on their own, sufficient to gain entry. Think of it like this, God and sin are like matter and antimatter(kind of), God is perfect and cannot allow sin into His presence, therefore, people being sinners by default and being unable to not be sinners under any circumstances are unable to enter His presence in Heaven by themselves or by their own works. Enter Jesus, the solution to "well, that's not fair" that is most people's reaction to the previous situation. By being God made flesh he is the only sacrifice worthy as payment to enter Heaven. Another way to look at it is this, one day, sooner or later, we will ALL stand before God under judgement for our actions and the way we led our life. As sentence is passed, and we are damned to hell for being sinners, Jesus stands beside us and says, "This ones OK! I'll take his punishment for him". In fact this has already happened, Jesus died and walked through hell before being resurrection on the third day.