I like the moderated recycle bin idea.
I've been to forums where thread deletion was not allowed and it sucked. I particulary like this one because you're free to delete posts and threads.
Besides, if you post in the wrong forum and realize before any mod can see it, you delete the thread and post it in the correct forum (this has happened many times, I remember).
IMO, users should still be able to delete their threads, but put on a moderated, private forum. BEFORE A MOD CAN MOVE IT BACK, he/she should ask the thread starter WHY he/she removed the thread. If the reason is something dumb and the thread is useful, the mod can move it back.
It doesn't mean all threads will get to be moved back. And the recycle bin should be like T&T, where threads get deleted after a period of time.
Just my .02$
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