I have had the problem of "getting into" operatic music for a while. In very few occasions, like in Philadelphia, I would hear a piece of an opera that would grab my attention.
This CD has been my entrance to this new world, although I have only half of one foot in!!!???
Maria Callas: The Legend
This is a fantastic piece, and she is an incredible singer, unbelievable. I found the CD when I was searching for the following piece from Carmen opera by Bizet. This is a truly magnificant short piece that I first heard on public radio:
Carmen: Act I: L'amour Est Un Oiseau Rebelle (Sample: Listen -- from amazon)
Also, related, watch this video related to the Bizet's Carmen.