I did read it in that order - ENDER'S Game, Speaker for the Dead, Xenocide, and Children of the Mind, then Ender's Shadow, Shadow of the Hegemon, Shadow Puppets, and Shadow of the Giant.
I'm just fascinated by the storyline of Xenocide because Orson Scott Card has carefully, and masterfully embedded some of the most sensitive themes in it: Superiority, Cultural difference, tolerance and acceptance, and Judgement. Who makes the rules? Who says what is right, what is wrong? Who gets to say what should be done and what shouldn't be done? Whose God must be worshipped? What language should be used by all people? Who is more important?
These are real-world issues that plague humanity on a daily basis. Some of us refuse to acknowledge it, others thrive with it, still others have to live with it and many die because of it. But these questions remain unanswered. In Xenocide though, these questions were partially answered. I love the way Orson laid it out through the story of Qing Jao and the people of Path, and Ender and Valentine, and Novinha and her family. The intricacies of their lives can be seen in the lives of people we know now--perhaps our own lives mirror them in some aspect. Then the Buggers and the Pequeninnos, who were sentient beings totally different from us--isn't this the way we look at some of the more bizaare members of the human civilization? Anything that is not native to us we treat as aliens--just like the Buggers, sometimes we are scared of those who are so different from us that we sometimes decide to wipe them out completely and we've done that many times too. People do have a tendency to believe that they are the only ones worthy of life. That they get to decide who stays and who goes.