A lot of the best opera recordings sound bad (historical, live, mono, etc).
Since you seem to like Puccini and Verdi:
La Boheme
Tosca -- you must hear Callas/diStefano/Gobbi, but it's in mono and sounds awful (by audiophile standards).
La Traviata -- The live Callas/Giulini La Scala is phenomenal, but again, it's in TERRIBLE sound.
Il Trovatore
For French, try Faust.
Since you seem to like Puccini and Verdi:
La Boheme
Tosca -- you must hear Callas/diStefano/Gobbi, but it's in mono and sounds awful (by audiophile standards).
La Traviata -- The live Callas/Giulini La Scala is phenomenal, but again, it's in TERRIBLE sound.
Il Trovatore
For French, try Faust.