I agree with Lynne. I don't think Dumbledore died. The only person who could stand up to Voldemort was Dumbledore and Voldemort was afraid of him. With him 'dead' it gives the opportunity for Voldemort to come into the open which is exactly what has to happen if Harry and friends can overcome him. Yes, Snape is really a goody too. All the signs are there, you just have to look for them.