I just love Hermione's character but it's hard to choose a really good moment. I like it when she sets the birds on Ron after she sees him with Lavender. It's kind of the only time where she actually confides in anyone about her feelings - the rest of the time she pretty much keeps herself to herself. And the part where she deletes herself from her parents' memory - it's so sad
Hermione did a lot of things... great things... but I really like her when she studies and figure things out... when she solves mysteries. Without her, the Wizarding world would have been in bad shape. She's brilliant... Holy Cricket!