I totally believe that Sirius is dead. There's something on another site, about Jo saying that magicals can communicate with each other even after death and that mirrors might play a role. My bets on the Erised playing a role rather than the mirror Sirius gave Harry - which is smashed at the bottom of his trunk anyway. Therefore, I think Sirius may well communicate qith the living again but it'll be pretty limited. It would be ashame to make too bigger a deal of Sirius 'coming back' I reckon 'cause dead is dead; let him go and get on with it.

Miecha: Ta so much for all your work and thoughts they're great.
Why does the Avada curse have to be green? I've discussed this somewhere else on this site but I get the impression that it's the magical and the wand maybe even the passion; the intent behind the spell, that determinews the colour rather than the type of spell. Am I wrong?