I absolutely do not want other members to be able to delete what I have posted. I think it is completely wrong for someone to think that they own a therad just because they started it. So I do not want the orginator of a thread to be able to delete the whole thread.
Think about a normal conversation in a room. Someone may bring up a subject and others join in, the conversation takes on a life of its own. Would you consider it normal for the person who brought up the subject to say "OK that's enough now, everyone talk about something else!"
I don't really have a problem with people being able to delete what they posted. But I am not sure how that is really different from deleting all the text. I see a place holder for the deleted post to be a good thing. It lets others know what happened. Much like the automatic notice that occurs when someone edits their post. Both of these help prevent the "what the hell happened here" issue. Information is a good thing!