I've only recently bought this, but it's already up there amongst my very favourite CDs. Karajan was born to play Wagner, his trademark "legato" at it's very best in particular on track 2, the Prelude from Lohengrin, Act 1, which is absolutely sublime. It reminds me of angels making their way up to heaven and getting "blown away" at the climax of the long crescendo as they arrive at the gates! (Probably not quite what Wagner had in mind, though).
Someone on Amazon's USA site wrote "These are some of the most passionate, romantic and utterly thrilling performances of Wagner orchestral music you can hope to hear". I only wish it were a 2 CD box, so it could include my favourite Ride of the Valkyries and more. It was recorded in 1974 when Karajan had spent years forming the BPO into the best orchestra in the world. Digitally remastered in 2001, so the recording quality is excellent.