As far as Wagner casts and conductors come (following his Parsifal) a new recorded Ring Cycle including: Jonas Kaufmann (Siegmund), Nina Stemme (Brünnhilde), Anja Kampe (Sieglinde), Mikhail Petrenko (Hunding), René Pape (Wotan) and conducted by Valery Gergiev don't come much bigger.
And the date to put in your diary? February 2013 will see the release of the first CD. However, this will not be Rheingold but, in an odd artistic decision but probably a good commercial one, Walkure. This will be followed with Rheingold in September 2013 with Siegfried and Gotterdammerung to follow in 2014.
If its anything like the Gergiev Parsifal it may be worth the wait.