I firmly believe that a) Dumbledore and Sirius are both REALLY dead (waaaaaaahhh!) and b) that Snape didn't want to kill Dumbledore, but was forced to by the Unbreakable Vow (which he had to take in order to avoid suspicion). I really do quite pity him.

As for his nasty behavior afterwards, well, the last time you did something really horrible--something you really weren't proud of--how full of sweetness and light were you toward your fellow man? All I know is, when I'm particularly ashamed of myself, I turn into a Bitch On Wheels and am unfit to be around. ;) Plus he had to then run off with the Death Eaters, and couldn't exactly be acting remorseful, now could he?

If my theories are correct, I think Rowling handled it all beautifully, even though it totally sucks. ;) I just hope that Hermione and Ginny both make it out of Book 7 alive (and Harry, obviously). Ron, to be perfectly honest, I could take or leave. *grin*

M