Most of these are film adaptations of opera; that way, you get the immediacy of cinema, as well as the opera. These are good films as well as good opera productions! I've linked to YouTube videos, so you can get a taste.
MOZART
Don Giovanni (1979 Joseph Losey, w. Ruggero Raimondi, José van Dam, Kiri Te Kanawa, Teresa Berganza) - Filmed on location in Italy.
Trailer:
Losey's Don Giovanni (1979)-- Trailer - YouTube
MUSSORGSKY
Boris Godunov (1989 Andrzej Zulwaski, w. Ruggero Raimondi)
Coronation scene:
Boris Godunov - Mussorgsky (Coronation Scene) - YouTube
PUCCINI
Tosca (1976 Gianfranco de Bosio, w. Raina Kabaivanska, Plácido Domingo, Sherrill Milnes)
Filmed on location in Rome - a classic.
Tosca (full movie), Kabaivanska, Domingo, Milnes. Director Gianfranco De Bosio 1976. - YouTube
Madama Butterfly (1995 Frédéric Mitterrand, w. Ying Huang, Richard Toxell, Ning Liang)
Puccini: Madama Butterfly - YouTube
STRAUSS
Salome (1975 Götz Friedrich, w. Teresa Stratas, Astrid Varnay, Bernd Weikl)
Strauss Salome Teresa Stratas 1975 ln 5 lang. Cc by Etcohod - YouTube
VERDI
Rigoletto (1979 Jean-Pierre Ponnelle, w. Ingvar Wixell, Edita Gruberová, Luciano Pavarotti)
Giuseppe Verdi - Rigoletto - Pavarotti, Gruberova, Wixell - Chailly - YouTube
La Traviata (1983 Franco Zeffirelli, w. Teresa Stratas, Plácido Domingo)
Verdi: La traviata (excerpt) - YouTube
Otello (1986 Franco Zeffirelli, w.. Plácido Domingo, Katia Ricciarelli, Justino Diaz)
Official Trailer - OTELLO (1986, Placido Domingo, Franco Zeffirelli) - YouTube
ERKEL
Bánk Bán (2002 Csaba Káel, w. Éva Marton)
Hungarian grand opera, with a mad scene and a killer of a confrontation scene.
Erkel Ferenc - Bank Ban - with English Subtitles - YouTube
SOMETHING LIGHTER
Rossini:
L'italiana in Algeri (1987 Schwetzingen Festival)
L'Italiana in Algeri Finale Act 1 - YouTube
Gilbert & Sullivan:
Patience (1995 Opera Australia)
If a local cinema shows opera broadcasts (from the Met or elsewhere), I'd recommend going to those, too.