While I can say with relative confidence that I'm an ontologist (believes in objective truths, objective rationality, objective reality and forms that stem ultimately from a source, creator or God) with an interest in pushing theology, the typical idea of heaven and hell that exemplifies the conditions of the afterlife doesn't quite cut it for me. In fact, it is more likely that I subscribe to another less popular set of ideas about what heaven and hell truly means (for which I will be accused of not endorsing the idea of heaven or hell at all, but let's see).
To begin with, for many thinkers, the idea of the afterlife as represented by the glory and beauty of heaven with its blue skies and white clouds and the torture and despair of hell with its fire and chains in such a humanly-conceived literal sense cannot be sufficient. The suspicion is there that it is possibly too embellished with a human-like idea of what the afterlife might be like, or even what one hopes the afterlife might be like, such that it is palatable and easy to understand for most people.
For me, firstly, I begin from Plato's conception of reality being a derivative of the divine - everything that we see in the world are imperfect forms of an objective source of creation (thus giving rise to all the evils and imperfections in our world). By analogy, there exists a perfect soul in each of us that is linked to the divine, only that it is shackled by the imperfect and material form of our bodies as we exist in the material form of the world.
To cut a long story short, from this idea of the perfect soul and the imperfect body, heaven and hell are states that our soul actually already exists in based on our actions and how we view our actions and ourselves. I am technically existing in living hell if I do bad things, and I know that I'm doing bad things to the extent that I am tormented by my bad actions (and awareness of them). The proximate measure for this is the conscience, through which guilt functions as the indicator of the sins we know we are committing, and through which our sense of responsibility to be good persons (based on the frameworks of morality and principles we establish as we grow) punishes us for if we fail to live up to the standards we set for ourselves and for other people. One's sense of karma also comes from the intricate workings of the conscience, as people with a strong sense of divine justice often see one's present misfortunes connected to a misdeed in the past, even though the two events might not be rationally linked.
Likewise, we are in a state of living heaven if we know we are doing good and living according to what drives us virtuously. This implies a responsibility even to pursue one's dreams, because those are things that drive us from the core of the soul (assuming those passions are virtuous ones and the soul is shaped virtuously). From this, it is clear that such heaven and hell states exclude people who are amoral, oblivious and/or do not have a conscience.
This is why the conscience has an important role. The only way one can feel guilt and understand one's sins is through a conscience (the sole adjudicator that resides in us, and punishes and rewards based on our innate sense of justice), and philosophy and religion often helps to build the conscience. People without a conscience can never be punished for their irresponsible actions because they will never feel a sense of guilt (however, I would strongly believe that the lack of conscience is rare and possibly a consequence of pathology - for instance, the mentally unsound probably do not have a conventional form of conscience and therefore can't be punished for their misdeeds).
Heaven and hell as reward and punishment end-states marketed to the masses attempt to indicate what it must be like to live a rightful or wrongful life, but it only broaches the divine justice system very very briefly and superficially. This is also what appears to be the morality of religion that almost all faiths teach - that you are free of your sin only when you believe. A sweeping tendency to relegate all non-believers to hell is commonplace. To some extent, such a claim serves a purpose of truth, because it is not so much a literal participation in the material form of the practice of Christianity, Catholicism or Islam, just to name a few, but more so that when one knows and responsibly participates in the divine order of the creator and lives a life based on his or her own principles of virtue, that one is free. Religion does serve as a way of reassuring oneself that he or she is still anchored to a set of virtues and faith, and the conscience is thus clear. I do believe that only when one adopts a faith for such reasons, rather than for reasons along the lines of socializing and attaining other forms of validation, does he or she truly establish a genuine relationship with God.
To even extend this further, if it is true that the soul is our perfect form that belongs to the divine, then the idea of a heaven or hell afterlife is possibly close to the idea of the inability to change one's 'positivity' or 'negativity' upon death. In other words, if all throughout my life I have been a bad person, then I am possibly an entity with lots of 'negative energy'. Will I want to die stripped of my body - the instrument, vehicle and means to be able to correct my soul into 'positive energy' - and remain a form of 'negative energy' forever? If the conscience remains with us as part of the soul after death, does this indicate an eternity of being wracked with guilt, personal anguish and torment?
In fact, to tie everything together, even the notions of past, present and future are hypothetical states of time that we conceive of in a bid to better understand reality. This causes most teachers of faith and religion to segment heaven and hell into the afterlife, and one's imperfect body reigning in existence in the present life. However, the past, present and future could very well all be states of time that exist within a continuum. In that case, a living heaven or hell might tie in very much with a holistic sense of what a life led either virtuously or through vice might truly be.
This, at least personally, appears to be more likely what heaven or hell might mean.