Best first operas

Like most opera fans, I am a bit of an opera evangelist. It’s hard to be my friend or acquaintance for long without getting dragged to the opera by me. However, after a few failed attempts at converting friends to opera fandom with inappropriate fare, I’ve drawn some conclusions about what’s most likely to get them hooked.

First, a few general rules:

• Comedies tend to work better than tragedies. While I prefer tragic operas and many of my friends now do as well, the bouncier, catchier music of comic operas usually gets people a bit more excited about the art form at first. (There are, of course, exceptions, and you will see some tragic operas on my list.)
• Sensical plots are a plus. Maybe it’s just because I went to an engineering school and was dragging engineers to performances, but the utter absurdity of The Magic Flute and Così fan tutte didn’t cut it. Start with vaguely plausible stories and go from there.
• Most people like tonality. You don’t have to stick to Puccini and Verdi–I’ve had success with Ravel and Poulenc and Wagner–but I wouldn’t make Wozzeck anyone’s introduction to the genre of opera.
• Fairly traditional productions are good for newbies. “Fairly traditional” is wide, and includes both sumptuous period productions and minimalist modern stagings. The important thing is that the production allows your friends to concentrate on the music and the drama. You don’t want them to spend the whole show trying to make sense of the fact that the chorus is in rat costumes, even if it’s actually a clever and reasonable directorial concept.
• Operetta can be an effective gateway drug. 
  

Here, then, is my ranked list of best first operas or operettas. My methodology involves an entirely unscientific combination of personal experience and random guessing, so comments and suggestions are much appreciated.

1. Il barbiere di Siviglia
2. Le nozze di Figaro
3. La bohème
4. La traviata
5. Don Giovanni
6. Die Fledermaus
7. Carmen
8. The Pirates of Penzance
9. L’elisir d’amore
10. Rigoletto

Does that seem reasonable to you? How have you successfully introduced friends to opera?