In an interview in the Telegraph JK Rowling says:
In the seventh and final Harry Potter book, there will be deaths of both goodies and baddies. She was talking to her husband, Neil, recently, after she had just written the death of one particular character. "He shuddered. 'Oh don't do that,' he said to me, but of course I did."
AIY! WHO GOT KILLED?! I WANT TO KNOW!