Firstly, no I didn't know a movie had been derived from Gurdjieff's work - I'll bet it's 'remarkable'!
When I was introduced to Gurdjieff 30 years ago, it was after a ten-year immersion in Western analytic philosophy and modern history.
His metaphysical take on the world was so radically different from my own, yet suffused with Gurdjieff's compelling aand humane voice. It was a genuine glimpse into 'the other' for me.
Influential book? I doidn't think so, until now. ;^)
I can't say that many of his 20th Century picks deserve to be on such a list, and there are a few notable omissions in the earlier centuries.
I scanned the list by quintiles, and from the earliest, I had read substantial portions of all but 4,7,3,2,and 3 of the works listed. 19 all told unread. I'm not ashamed.
Amongst 20th C. writers, perhaps consideration could be given to the influential Mackinder and Mahan, Sorel, and it irks me to say - Lenin.
Spengler and McLuhan.....
I quit! ;^)
For those so inclined a related site has reproduced MSS's entire entry on Gurdjieff...
http://www.gurdjieff.org/G.2-3.htm