I don't think this thread has been done before, or at least I don't remember it, advanced search yielded nothing.
Last week I was listening to A Sort of Homecoming by Anathema, Sanctitude by Katatonia and A Night Under the Dam by Green Carnation a lot, and I realized I really like when rock and metal bands go acoustic, either in the studio environment or live.
What are your favourite acoustic performances by rock or metal bands? Could be songs, albums, studio, live, anything.