PiL's Poptones is one of the most beautiful pieces of music I know. It blew me away the first time I ever heard it (especially coming after the "difficult" first 3 songs on Metal Box), I remember sitting there in awe as it played. It's lovely - hypnotic, haunting - very unique, I've never heard anything else like it. The guitar and bass parts are mesmerizing. I've been reading Jah Wobble's autobiography (an excellent read) and he gives a slightly different version of the inspiration for the lyrics that I've heard for years (both are told here). He also says that it's Keith Levene playing drums on the track, which I didn't know. Wobble himself played drums on The Suit.
The live Paris Au Printemps version:
Live on The Old Grey Whistle Test:
And then there's this "infamous" performance (along with Careering) on American Bandstand in 1980. Good anecdote on the YouTube page. I'm amazed this ever even happened. Metal Box is about the farthest thing you'd think of as being on prime time American TV.