Being something of a novice when it comes to opera, this is the first full version of Nabucco I have seen. I checked the DVD out from the library, and although the picture quality isn't excellent, the sound recording definitely makes this version worthy of its DVD release. The music and singing are absolutely top-notch, more than making up for a silly, bumbling and boring story. I recommend watching this without the subtitles, as the text will only distract, and detract, from the music.
The best singer here is Abigaille (Grace Bumbry), but the entire cast have fine voices. Verdi is to opera what Shakespeare is to literature, and his singular talent for opera is demonstrated by the way this composer always gives precedence to the voices. The music, suitably great and grand as it is, always plays back-up to the voices, never drowning them out like certain other composers one might mention (*cough* Wagner *cough*).
I rate this production a humble 7 out of 10, for although very little is wrong with the music, the scenography is less than innovative. It is classical, to be sure, but Nabucco is one of those operas that do not benefit from a classical production, because the story is obsolete and not very interesting in its original form. Turning it into some sort of flashy avant-garde surrealist exercise, as I understand is done in many subsequent productions, serves this tale far better. What's important to modern stagings of this opera in particular is to maintain the music, and keep reinventing the setting so that it backs up the music and singing through innovative and imaginative visual impressions. Forget the story and the meaning of the lyrics and focus on amplifying the emotional impact of the brilliant music and the voices.