Hi Doc-
Since I'm one of the proponents of the "we really don't want to reincarnate but we generally discover that we have to" school, I'd like to add my two cents worth.
Our state of existence requires whatever we feel that we need in order to be whomever, or whatever, we believe ourselves to be. This requirement is non-negotiable, because it arises as an existential precondition for whatever that existence might be. The association between the felt need and the state for which it is felt is termed "attachment". We generally sense it as desire, craving etc.
There is nothing specifically wrong with the present state of existence as embodied beings, but with that existence, because of its nature, we always have the problems, as Siddhartha put it, of "sickness, old age and death". Buddhism sums that up by saying, "Life is suffering".
Suffering is caused by bad choices, some of which are inevitable, because in any situation, we have only a 50:50 chance of making the correct decision, reduced by the degree of exploitation by others. We counter this by education, and especially by spiritual education through which we learn of the possibility of living better than by chance alone. Thus we develop morality and rules of behavior, and we migrate toward life with others of similar kind. We use the term "enlightenment" for the evolving awareness of a better reality, and especially the spiritual meaning of that awareness.
In the end we live in a state called "liberation" or "satchitananda" in which we cease to create negative karma because we have learned how the cause and effect nature of the world operates. And that means that in general everything in the world operates in accord with whatever we do, so that we either make no mistakes, or so that there is always a suitable work-around by which to avoid discomfort. This is the lifestyle of gurus, saints, prophets etc. It can be rigorously defined using relatively simple logic.
There is no overwhelming reason to go on to a different embodiment, except that when we get rid of the body we also get rid of some of its quirks, such as sickness, old age and death. There seems to be a seductive attraction for the blissful experience of existence as a free spirit. With death, the limitations of motion associated with a body are said to fall away. As in an OBE, or deep meditation, there is an awareness of the infinity of love, wisdom and joy that emanates from Godhead, and, to the degree that we messed up, an intense regret that we denied this to ourselves.
The sense of regret is often associated with empathy and compassion, as we directly tend to sense whatever we did to others as something we have done to ourselves. This can lead to guilt, to remorse, to an unbelievable feeling of unworthiness. And, at the same time, it tends to lead to an equally intense desire to "do it right next time".
This is the hinge about which reincarnation seems to revolve. We seek the chance to improve, and to obtain it we accept the risks and problems of a human life. For those who have mastered the human levels, there seem to be a very wide range of spiritual levels of attainment, all of which are a lot more pleasurable. And, all of which bring us much closer to Godhead. To make an arbitrary choice of being human as opposed to being an advanced spiritual being is thus like choosing a piece of broken glass over a flawless sparkling gem. You can't eat either one, but the gem has more to offer in giving pleasure to the beholder. (And, since everyone is everyone else, we don't lose anything by becoming spiritual.)
It seems that the process of death and reincarnation takes us through a cycle of decisions of this general sort. Notice that these are primary process operations, not thought about in the sense of "how many angels can fit on the head of a pin", but felt, sensed as turnings and impulses of our existential basis, right along with all other primitive emotional states.
In a very fundamental sense, life amounts to the accumulation of emotional states through manipulation of their embodiments in matter, like working at a job to buy a ticket to the opera which gives us pleasure. At death the manipulation ends, rational thinking pauses, and these primitive impulses are what comprises our nature. They manifest as "forces" or "tendencies", and return to us the results of their propagation through the world as a reflection of our existential nature at that time. This is both like "thinking" in the sense that it leads from pre-conditions to conclusions, and also it is like being dragged through a logical knothole because all we are is what we were and what remains. Given that state, we tend toward a rebirth in which we can get rid of our imperfections. Often we are terribly harsh on ourselves in an effort to improve. Reports from regressions appear to support this cycle.
Looked at from "outside", this suggests that after death we perform a sort of "feel how we are" kind of review, and then observe areas in which we wish to improve, which is the attachment that draws us back to embodiment. At the same time, in the spiritual state, as in deep meditation, we are aware that there is a better way to be whatever we are, so that there is a very definite attraction to spiritual growth, and, ultimately, merger back into the Source from which we initially came, together with the experience of unending pleasure, wisdom and love.
The tricky part seems to be that to become one with God we have to give up being human. In its place we become super-human, but in a different way. Rather than a personal life with personal attributes, the super-human state begins to generalize into non-personal, non-individual states. What gets lost is the ego-distinction between self and others, and what is gained is the oneness with all. The end of the process is, as Edgar Cayce put it, "to become co-creators with God".
Fortunately, all of this becomes quite clear in meditation, which is one of the main reasons for meditating. It's fun!
dave