I tend to agree. Snape in a way, I think, was much like Draco when he was younger, too eager to please those he idolized before really figuring out what they were about. He inadvertantly came accross a juicy piece of info when he overheard Trelawney's prophecy and made a beeline for Voldemort hoping to get on his good side.

I think that Snape really has switched over to the 'good' side and is probably the truest member of the Order of the Phoenix. I also think that he will probably give his life in book 7 for his beliefs. He still hates James and Sirius for how they treated him in school. He is acting out of the instructions of Dumbledore and killing Dumbledore may have been planned, may have been an act of mercy, or may have been unavoidable owing to the oath given to Draco's mother.