I see Nirvana's cover of Bowie getting a lot of credit in this thread, and deservedly so. However, getting overlooked is Nirvana's cover of a different song from that very same "Unplugged in NYC" session- their cover of The Meat Puppets' "Lake of Fire." I'd say it's an even better cover than "The Man Who Sold The World," and I haven't seen it mentioned once.