Greetings:
This subject is as fascinating as it is complex. I take the position known as conditional unity, which is kind of a cross between a strict naturalist point of view (our "spirit" dies when we do) and strict dualism (the physical body and soul (or mind) exist in separate realities).
I believe that at death, the unnatural occurence of our soul/spirit separating from our physical bodies into heaven (or hell, depending whether or not you've accepted Christ) into God's presence. As this is our unnatural state, our soul/spirit longs to be back in a physical form, but is temporarily overshadowed by the fact that we are in His presence. In closing, separation from the physical body is only a temporary state. We should caution ourselves not to put to much emphaisis on either the physical body or the soul/spirit that is our breath of life. Anyway, that's my two cents on the issue. God bless!
In Christ,
Ichigo(Matt)