I'm not into opera, but I could look at that blonde's hair all day.I love Anna Netrebko & Elīna Garanča – Offenbach's Barcarolle.

And perhaps tho most Adagio from Aram Khachaturian - Spartacus.
The day before you posted that, I had listened to Spartacus. So I listened that day too. I found myself humming the main melody that day too. Such a powerful song that goes through the emotional gamut.
It's also interesting to hear a different orchestra play a song you know, because their timing on certain parts is different, so you're almost more engaged. Still it's like if you hear a song, you tend to like the first version you heard of it the best.