I think it would be nice to have a list of passwords that sabnzbd can check if it finds an archive that needs a password and has not had one defined in the name of the nzb (using the new feature in 0.5). I do realize this would become very inefficient if the list was too large, but if kept to a respectable level it might not be too bad. The situation for where I saw the need for this was with tv shows. Now that there are many ways to automate tv show downloads, this would help. There are nzb's being posted with password for all different shows and often the same password can be used for many of them. Would also be good for just general nzb's with passwords as often a common password is used.
Side question, there isn't a way for you to define a password after a nzb had entered/finished (and failed) post processing, is there? Would be nice if you could define a password after and then re-process, though I understand that it likely a lot to implement.