I will donate the the cord blood from my baby.
This is just my thoughts. As the cord pulses, yes arterial blood runs from placenta into baby, but venous blood is running back at the same time. My baby will have been getting the nutrients from the cord for 40 weeks, and i dont think in the last 3 min he/she will get any super special blood.
If i have a sick/dying baby in the future i would like to think that someone else has donated their babies cord blood inorder to save mine.
It is not the volume of blood that is important, so much as the stem cells. They can be used to generate red blood cells and cells of the immune system. This can treat immune system diseases such as leukaemia, and autoimmune diseases.

Yes i agree my baby could benefit from the blood, but perhaps not as much as a baby with leukemia.