Just sharing on the important even after last breath.
In usual circumstance, basically more than 90 percents of soul of people will not leave their corpse immeditately, this is due to their loving themselves more than loving others, loving their possession and loving this world. As the physical world is so much beautiful and enjoying, it does not have a basis in the true happiness. It is present to help one another enjoy the true happiness and cannot be clinged on them.
http://moderatemuslimvoices.blogspot.sg/2011/05/why-muslims-bury-within-24-hours.html
Muslims feel the world as temporary place, when soul leaves the body there is no reason to keep the body and real life begin after death.
It is contradictory that muslim cannot be cremated as the corpse body is souless immediately upon death. http://en.wikipedia.org/wiki/Islamic_funeral
Muslims ought to leave the dead for at least more than 8 hours untouch, and also gather together to offer their collective prayer for easing the soul. As the dead usually does not immeditately depart its body upon death, so reminding the dead to be calm and follow along with their prayer is utmost importance, and it will ascend from the merits & blessing of prayers as well. There are cases of resurrection even after death, so burying the dead within 24 hours is not encouraged, at least 3 days.