Koyaanisqatsi is brilliant, if you like that style of film then I recommend getting Bakara and Samsara (if you haven't got them already).
Powaqqatsi is ok, but in my opinion Naqoyqatsi is pants .Hadn't heard of those before, cheers. They're both on Spotify so I'll check them out.
There's also Powaqqatsi and Naqoyqatsi (both also on Spotify), but Koyaanisqatsi is the only one I listened to/watched before, mainly because of Pruit Igoes use in GTA:IV.
Seeing all the worry over the doday stuff - is lost in transit such a very common thing for Royal Mail to happen? oo