Ha, I found cultural treasurez!
http://www.floydpodcast.com/ podcast number 51 is The Wall Demo.
Wow, for Floyd-fan like me this is extremely interesting stuff (even as The Wall is my least favourite of the "Big Four" albums). And The Wall is one of the most famous albums of all time, which makes it even more interesting.
Especially my all time favourite song, Comfortably Numb is rather intriguing. The basic music (by Gilmour) shows its pure geniousness here better than in album version which has much flusher and deeper sound textures, orchestrations etc since it's simply more audible.
Of course it's not good as album version (d'oh) since it's that, well, demo. But it's easier to pick up basic music behind the superb soundscape Floyd records tend to have. Also, Water's original lyrics for CN are ****. Gilmour's music and solos make the demo listenable, even great (sucky sound doesn't bother much), but no way I'd listen this one for lyrics. The final version of lyrics is so much beter it ain't even funny.
Run Like Hell doesn't have lyrics yet. Surprisingly it works as instrumental song quite well. The Thin Ice has some interesting synth playing as does Young Lust, Mother sounds surprisingly good, Water's non-studio-magicked vocals tend to be horrible etc. etc.
Very interesting if you enjoy "making off" stuff which this kinda is
edit: in b4 "u listen with microscope"!