While it's hard to say anything is the best of anything ... the best band ever? ... the best song ever? ... Topics of discussion that are always up for debate ... So, while I believe there is no such thing as 'best' when it comes to art, of which "Nostradamus" unapologetically is, it is one of the 'best' albums of all time for me.
That being said, "Nostradamus" is nothing short of an epic masterpiece -- as it encompasses all their skills, ranges and abilities. We have the metal, the opera, and the orchestra... which is a true marriage that simply showcases their talents and how diverse they really are. Hopefully it also tells us we get better with age... (I can only hope, lol.)
I think we see a glimpse of this, a long time ago, in "Sad Wings of Destiny" -- Dreamer Deceiver. Anyone else out there think so?
PS -- i play the violin & guitar, or used to until a recent, very unfortunate accident to my L-hand... anyway, in the credits of "Nostradamus", they credit the violin as "real strings". I thank them for that.