I really loved the Ender's Game series because, for the most part, Ender was quite the opposite of Harry.
To anyone who can associate these feelings with theirs: Please go read this fanfic. Try to read at least through chapter 5, because the author states that the common consensus is that is when the story hits its stride, and I concur with that sentiment.
Please note that I have only made it through chapter 7 so far so I could be setting you up for disappointment, but given the number of chuckles I've had, I don't think this will be the case.
Harry Potter and the Methods of Rationality