And I'm jumping in as well just to mention this issue elsewhere, that is, the issue of "just ignoring" the Slytherins. The Slytherins (with Snape being the most obvious problem) are often very aggressive. Sometimes they are openly teasing and trying to get a rise out of people. But they aren't *always* doing that. It's Gryffindor policy to ignore or be defensive by default. In the readthrough of PS more people noticed that Draco's actions with the dragon could easily be read as an attempt to make some connection with Harry. Yes, he's going about it in an aggressive way and it's very easy to see why the Trio takes it as they do, but for many readers it still comes across as Draco blatantly trying to be included. I feel the same way when he grabs Neville's Rememberall the first time and asks what it is. It's aggressive, it's haughty, it's Draco's style, but it becomes a fight when Harry and Ron rise up together hoping for a reason to hit him. Draco's opening conversation in the robe shop is also often painted as being a bullying one when to me it doesn't seem that way at all.

In this book there's the scene on the train where Draco comes in seeming to want to talk about the tournament, assuming these people will also be in the know. He arrives with an insult to Ron, but I just don't see the Slytherins as trying to start a fight there, though the Gryffindors respond to it that way.

Again, this isn't to paint a picture of the poor Slytherins trying to be friends while the mean Gryffindors smack them down, but when I read some of those scenes I also don't see a situation where the Slytherins are always attacking and the Gryffindors can only ignore or defend themselves.