Wow, this is beyond amazing. I am still listening. I also love that this dude did not make the mistake of copying vocal melodies note by note (including the exact rhythm) like it is the case in many orchestra arrangements of rock songs.
Also, this proves the musical quality of DTs music. It's not only rock or metal. It is composed brilliantly, it is complex a well thought through enough to fit into an orchestral arrangement - plus, the orchestra is really USED here, it's not only laying down long notes and sounding nice.
#EDIT: I just got major goosebumps at 7:55. WOW!
If it wasn't too log for that, the guys from DT should have used this as the opener piece for their concerts!!!