Heaven, Hell, Purgatory, Sheol, Jannah, Jahannam, or reincarnation are all different terms for what happens post death. It is hard to imagine a living breathing soulful human being just perishing to dust, so Islam, Judaism , Christianity, Buddhism, Hinduism and many other religions have developed representations of the passing of the human soul to a different plane.
This is not necessarily a problem when practiced in its purest form. You sin while alive you go to Hell; you live a good caring life you go to Heaven. The problems arise when the religions begin to forget this basic premise or offer exceptions to the rule. Evangelical Christians, and most forms of Islam believe in exclusionary admittance to Heaven or Jannah. If you are not an Evangelical Christian and have not gone through the rebirth and acceptance of Christ you will not be one of the chosen. If you are a not a true believer in Islam and have not fought for its existence you will be excluded from Jannah in some of the more radical sects.
This bastardization of the concepts of Heaven and Hell affect the practices of good and evil in the here and now. They also skew the concepts of who is right and who is wrong. We forgive those that have wronged in their life, but have seen the light and accepted Christ or have killed in the name of Allah. We immediately condemn those who haven't seen the light, yet lead a life of non harm. We see evil in those that will not be among the selected few to join God in the next coming, and see only good in those that follow our particular set of teachings. We seek to grow the ranks of the accepted, therefore swelling our churches coffers to further our cause. After all, we are the true believers.
Now this is where it gets dangerous. There was a reason the concepts around the separation of Church and State were incorporated into our Constitution. If we allow corruption of the government, or undue influence from one religious form, we immediately create an exclusionary condition. Exclusionary conditions allow the sect with the influence to incorporate their particular views in ways that are not strictly influential, but through enforcement. Religious beliefs should be gained through introspection and analysis. You should find your religion, it should not be thrust upon you.
The US is leaning dangerously towards joining many Islamic countries in the practice of exclusion. The Christian right is attempting to manipulate our government to formulate laws that undermine the ability of others the right to practice their religion as they see fit. The church and political leaders leading this charge are not doing it because they really believe in their particular form, but because they realize the power of exclusion. Exclusion elevates the true believers above everyone else; it furthers their cause and status. The status in their eyes is achieved in the eyes of the Lord, and not through traditional societal peering. Answering to possibly fictitious beliefs removes the normal checks and balances that are achieved through majority consensus in a modern democratic society and undermines its premises.
The will of the people is no longer achieved and true freedom is removed through the exclusionary practices of the afterlife belief process.