Full mottos:

1. Just because it's taken you three years to notice, Ron, doesn't mean no one else has spotted I'm a girl!

2. It's sort of exciting, isn't it? Breaking the rules!

3. Just because you've got the emotional range of a teaspoon doesn't mean we all have.

4. I hope you're pleased with yourselves. We could have been all killed -- or worse, expelled.

5. Books! And cleverness! There are more important things -- friendship and bravery.

If you have any other ideas/suggestions, just post them here, and I'll add them to the list =)

and 1

It sums her up quite well ;)

Awesome!