Christians have long been interested in the nature of the afterlife as it pertains to unsaved people. Basically, there are three options: Traditionalism (Protestant conception of hell), Annihilationism (or conditional immortality), and Universalism (where the unsaved spend a period of time in "purgatory"). I am a hopeful Universalist, but I recognize that the other viewpoints are possible.
The traditional view of hell emphasizes that God is not only a God of love, but also a God of justice. It views God's law as inseparable from God Himself, and thus all sin is primarily against God. Sin itself may be finite, but since it is against an infinite God, this creates a debt that can never be paid by a finite creature, and thus the punishment against it can never be fulfilled. As a result, God himself needed to become a man, and it was only God himself who could pay the penalty that God demanded. I find this way of thinking to be compelling. I agree that God and His law are inseparable. However, it is not without some difficulty. If we assume that God and his law are inseparable, one of God's essential attributes would be that he is just. However, in the traditional view, justice is never actually satisfied. As long as there is punishment to mete out, justice never receives her full due, and this means that one of God's essential attributes would fail to be realized. Jonathan Edwards also recognized this when speaking of the eternal damnation of sinners by saying, "But yet there never will come that particular moment, when it can be said, that now justice is satisfied." The fact that justice is never satisfied makes me doubt the traditional view, but it still remains a possibility depending on what extent God wants to make his wrath the backdrop to his mercy and grace (Romans 9:22-23).
Annihilationism (or conditional immortality) is the belief that unsaved people will cease to exist after a period of judgment and temporal punishment. Since "living forever" was not an inherent characteristic of Adam's nature (Genesis 3:22), this viewpoint allows the words "perish," "destroy," and "death" mean what they most naturally mean. The lake of fire is the second death where justice is served and the whole existence of unsaved people is consumed. Conditional immortality is persuasive and some influential theologians such as John Stott were proponents of it. However, the meaning of "living forever" in Genesis 3:22 may imply that there is such a thing as "dying forever" where the death is not nonexistence, but a life separated from God. Granted that Adam was in a state of probation, his obedience would have earned him life in the closest fellowship with God forever, but alternatively, it is also possible that his disobedience would have earned him a life of separation forever. As a counterargument, it can be pointed out that only God himself has immortality (1 Timothy 6:16), so man was not created inherently to live or die forever. The reward of "living forever" was only promised to Adam if he obeyed; otherwise, as an inherently mortal man, he would "surely die" (Genesis 2:17) for his disobedience.
Universalism is the belief that all (or nearly all) unsaved people will eventually become saved through a period judgment and corrective punishment ("purgatory," for lack of a better word). It takes a literal approach to passages that say that Jesus is the Savior of the world and that He recovers everything lost in Adam (John 4:24, Romans 5:18-19, 1 Corinthians 15:22). It views limited atonement as a short-term function that pertains to the "special" salvation of God's elect who, in the afterlife, are used to shepherd the nations with an iron rod (Revelation 2:26-27 LEB) in order to apply the effects of unlimited atonement (1 John 2:2) and universal reconciliation (Colossians 1:20). This viewpoint allows for justice to be served with the expectation that every knee will eventually bow in praise and thanksgiving (Revelation 5:13) to Jesus (whose name literally means "Jehovah saves") to the glory of God the Father. The result is that, presumably, justice and glory will be maximized when all people are put in subjection to God. The weak point of this viewpoint is that it takes some verses literally, but others figuratively, such as those that speak of "perishing," "destruction," and "death," or those that speak of "eternal" punishment and contempt in the same context as eternal life. It also depends on some speculation.
Obviously, there is much more that could be said about each viewpoint. However, as mentioned above, I am a hopeful Universalist. I have written the following articles defending my belief in this "greater hope."
Eternal Hope by F.W. Farrar