If you do not see the value in Christian apologetics I strongly recommend that you read Tactics: A Game Plan for Discussing Your Christian Convictions by Greg Koukl (if time is an issue, just read chapter 2).
I think all the following issues are worthy of discussion and debate.
“For I say to you that unless your righteousness surpasses that of the scribes and Pharisees, you will not enter the kingdom of heaven" (Matt 5:20).
Were the scribes and Pharisees trusting God? No they were not. No one can please God, no matter how many good things they do, if they refuse to trust Him. When a person trusts God, He regards their trust as righteousness. If a person's work is a result of trusting God, He is pleased with that. That's living faith (James 2:17). If a person's works are a result of trying to earn God's love (or a result of trying to keep his love, which the scribes and Pharisees were trying to do), then none of their works will be pleasing to Him; their starting point is doubt; their starting point is disbelief. They do not believe that God's love is unconditional. When a person works to earn God's love, He regards their works as filthy rags. (Isaiah 64 is talking about a people who were not trusting God; that's why their works were disgusting to Him.)
Many believe that the Bible teaches that a person cannot have a relationship with God unless they are sinless. But this is mistaken. Sinners can have a relationship with God if they start to trust Him. God does not require perfection for a relationship with him to begin, all He requires is trust. See here.
When we say God is just, what do we mean by the word "just"? What constitutes perfect justice? See the Sermon Justice.
Was C.S. Lewis favourite author, George MacDonald, a Christian?
Which is biblical, Imputed Righteousness of Christ or Imputed Righteousness through Christ?
Do we sin by nature or by choice? You might be surprised by what the early church believed. (If a person has never heard of Jesus is it inevitable that they will always choose to disobey their conscience? Or do they choose to either obey or disobey their conscience? If we know who Jesus claims to be and what He taught, can we choose to trust and obey Him or not? If we can choose we are responsible and are to blame for disobedience, but if we cannot choose then we are not responsible for we did not choose to do that which is wrong.) But can we really choose what is good?