Upvoting because someone else is honest to admit Phillip Glass is monotonously repetitive.
Nice list BTW !
And for something completely different: Us and Them: Symphonic Pink Floyd by London Philharmonic Orchestra http://www.amazon.com/Us-Them-Symphonic-Pink-Floyd/dp/B0000040UZ/
The most epic album I ever heard (personal taste obviously) is "Us and Them - Symphonic Pink Floyd". I could listen to it nonstop. I close my eyes and it becomes a journey. The last track is trippy as hell.
The thing is, I don't listen to too much regular Pink Floyd (sorry if that bothers anyone), but it's my favorite orchestral album.
The Royal Philharmonic Orchestra ♫ The Symphonic Pink Floyd https://www.youtube.com/watch?v=IBGeex66_t8
https://www.amazon.co.uk/London-Philharmonic-Orchestra-plays-music/dp/B0000040UZ and that also looks like a Roger Dean cover.
All quite interesting to add to the collection.
Not downplaying the grandiose that is Dark Side of the Moon, but you should check out the Us & Them: Symphonic Pink Floyd.
Start here: London Philharmonic: Symphonic Pink Floyd
This is definitely the gateway drug of classical music.