Kal,
What is the Callas opera performance you like best?
I must admit there has never been a better Vissi d' Arte than Callas / Di Stephano/Gobbi /Sabata.
"When opera lovers start thinking about vital recordings, one in particular is almost always mentioned: EMI's 1953 "Tosca," with Maria Callas, Giuseppe di Stefano and Tito Gobbi in the leading roles and Victor de Sabata conducting."
The Met borrowed the Salzburg production -- available on Blu-ray: http://www.amazon.com/gp/product/B001MRMRS8/ with Netrebko. As I might have said before, I rented the disc from Netflix and ordered my own copy the day after I watched it.
BTW, I finally bought the Valencia Wagner Ring cycle conducted by Zubin Mehta that I believe Kal mentioned near the start of this thread. After enjoying 15 hours of Wagner, perhaps it's time for another viewing of the Salzburg Traviata...