The type of traversal you should use really depends on what it is you are trying to do.
For example;
Postorder would be used when deleting a tree, as a node can only be deleted after is left and right subtrees have both been deleted.
PreOrder would be used when you want to copy a tree, as the parent node needs to be created before you can create subtrees for that particular node.
Hopefully this will help you : http://www.geeksforgeeks.org/618/