Now that Steve has mentioned Solti/Chicago, I'll throw in a nomination for their Beethoven Symphony No. 9 on London (CSP-8). This is the same recording MoFi released, and did an ok job with it, even though the original London is a tad better.
While we're on the subject of Decca/London, how about the Mahler 2nd with Mehta and the Vienna Philharmonic. I am listening to the Japanese pressing (KIJC-9139) tonight. It would take 4 reels at 15ips, but it is one of the better readings of this big work that I have heard.