My personal belief is that there are some sins considered more destructive than others. As far as being offenses against God and God's will then all sins are equal in that they mean we have fallen short and offended God. There is also blasphemy against God's Holy Spirit which many will attribute to different things. Without going into the various meanings or descriptions of what that might be it is surely the most serious offense when it is referred to as the unforgivable sin.
As for sins that Christians commit Paul had something to say about one sin in particular and a reasoning for specifying that sin as more damaging to the Christian.
1 Corinthians 6:12-20 (NIV) 12 "Everything is permissible for me"--but not everything is beneficial. "Everything is permissible for me"--but I will not be mastered by anything. 13 "Food for the stomach and the stomach for food"--but God will destroy them both. The body is not meant for sexual immorality, but for the Lord, and the Lord for the body.
14 By his power God raised the Lord from the dead, and he will raise us also. 15 Do you not know that your bodies are members of Christ himself? Shall I then take the members of Christ and unite them with a prostitute? Never!
16 Do you not know that he who unites himself with a prostitute is one with her in body? For it is said, "The two will become one flesh." 17 But he who unites himself with the Lord is one with him in spirit. 18 Flee from sexual immorality. All other sins a man commits are outside his body, but he who sins sexually sins against his own body. 19 Do you not know that your body is a temple of the Holy Spirit, who is in you, whom you have received from God? You are not your own; 20 you were bought at a price. Therefore honor God with your body.
When a Christ sins sexually then they are committing that sin with and against their own body and that's where God's Holy Spirit dwells, along with our inner spirit and thus because of that Paul list that sin as more damaging.
It is also, I believe, important, when talking about sin,, to realize that even though mankind is slave to sin and are sinners God provided a way to escape His assigned judgment against sins and that is through the blood sacrifice of Christ, on the Cross. God, Himself became a scapegoat for us, someone to take the penalty of our sins upon themselves, so that we could appear sinless to God when it comes to Judgment against those sins. Fort those who reject Christ Sacrifice then they will face Judgment without an advocate.
As for what that judgment will entail I do believe that some sins are treated far more grievous than others but everyone sins, even Christians, and continue to sin for no human is perfect however for those who accept God's Gift, Christ sacrifice then they, as far as judgment goes, will appear as without sin for their sins are and were covered by Christ blood.