Other than Vladimir Ashkenazy's performance of Rachmaninov's Second Symphony with the Royal Concertgebouw Orchestra (I believe), this classic reading with Andre Previn leading the London Symphony Orchestra---the first fully uncut performance of the piece---is the only performance of this wonderful work that I've heard, and frankly I'd be just fine having only this recording in my library to represent the work. Previn's tempos in all four movements may be deliberate, but still the reading as a whole never fails to convince. What matters most with this piece is that Rachmaninov's great melodies and soaring emotion are not shortchanged by either conductor or orchestra, and on that level the LSO and Previn do not disappoint. They are masterful in all four movements, but it is the third movement Adagio that a listener will most likely remember most. It may be slow (Ashkenazy was slightly brisker here, while Mikhail Pletnev, in his more recent DG recording, even more brisk and unsentimental) but it still packs an emotional wallop.
The couplings are also very good, particularly the short and sweet "Vocalise." Right now, this is one of my favorite classical recordings, and my enthusiasm for it is not likely to lessen anytime soon.