Firstly I do believe we have a spirit or soul - yes I fundamentally believe that there is some vital spark that makes each individual unique. I ought to I wrote a 12 page essay on my concept of Northern Soul!
Personally I think that my spirit and body certainly do live on - my spirit is in the memories of my family and loved ones which will echo down the generations, physically the atoms that I am comprised of are eternal as well.
Hmm

is there a difference between what is spirit and what is soul? This would be related to the transmigration of souls or reincarnation. Whether we have an eternal soul that can return to the world soul and then choose to transmigrate / reincarnate is the great mystery...
The Dictionary suggests this for Spirit:
1. the principle of conscious life; the vital principle in humans, animating the body or mediating between body and soul.
2. the incorporeal part of humans: present in spirit though absent in body.
3. the soul regarded as separating from the body at death.
and this for Soul:
1. the principle of life, feeling, thought, and action in humans, regarded as a distinct entity separate from the body, and commonly held to be separable in existence from the body; the spiritual part of humans as distinct from the physical part.
2. the spiritual part of humans regarded in its moral aspect, or as believed to survive death and be subject to happiness or misery in a life to come: arguing the immortality of the soul.
3. the disembodied spirit of a deceased person: He feared the soul of the deceased would haunt him.
Looking at point 1 in both dictionary references it would suggest that the the body, spirit and soul are separate but related and that it is the spirit that connects the body with the soul. This is rooted in Christian thought but also in ancient Germanic thought, so it may be a rooted in our earliest human concepts that have since diverged into the different religions. In Germanic thinking the World Tree would be the home of the World Soul and it's fruit the individual souls.
So can my soul transmigrate? I like to believe it can but also accept that it may well not, in this respect my mind is still open.
Death will be the great revealer... or not.

Most dear is fire to the sons of men,
most sweet the sight of the sun;
good is health if one can but keep it,
and to live a life without shame. (Havamal 68)
http://gewessiman.blogspot.co.uk