Originally posted by shellytt
About Neville, I believe that he would have been brought up in the Wizarding World, even if he lived with his mother's family. (They were pure-bred I think).
So being the orphan, growing up in the wizarding World, with all the attention and adoration that he would have gotten as the Boy who lived could have both negative and positive effects on how Neville's character eventually is perceived.
Harry's character in large part was more humble because he was never really exposed to the "celebrity" of the Boy who lived. When he did become aware of it, he was still more or less secluded in Hogwarts, so I still don't think he got the full extent of the adoration that Neville would be exposed to growing up. This celebrity would have a definite impact on teh way that the orphan Neville viewed the world and his place in it. He might have even been more open to the possibilty of the ultimate duel with Voldermort than Harry would have been. More confident in his abilities to fight the Dark Arts and to my thinking he may have been a little more arrogant and felt more entitled. Remember we can't let what we know about Neville now to influence how we think he could have been.
Now another question that arises- Would Harry have still been friends with Hermoine - the studious, serious girl? This is assuming that Harry and Ron have already been friends.
Good question; I don't know, but I think there's a chance, because to me Hermione always sounded like a second Lily, though Hermione was definitely more strict with the rule breaking thing. Growing up with his parents, I think Harry would have been like a bit of both of his parents: a little cocky, mischevious, and "stuck-up" like his father, but not as much as his father, because he might have the humble and accepting nature of his mother. But then again, James changed before he married Lily, so the "stuck up" attitude might not be there.
Harry and Ron would have had a closer friendship if they were friends from childhood, and they might have been more accepting towards Hermione's strict "no nonsense" attitude.
One thing we're all forgetting: Voldemort found and killed the Potters, because Peter Pettigrew gave away their hiding place. If Neville had been marked as the Chose One, and if the Longbottoms had gone into hiding, who says the person they would have trusted with the Fidelius Charm would give away their hiding place? they might have remained in hiding for many years, and Neville would have grown up in the seculsion of the Fidelius charm with only his parents as companions.
Voldemort might never have been "defeated", there would be no Boy Who Lived, and the Wizarding World as we knew it in the first book would not have existed.