What a great piece of music Johann Strauss's Emperor Waltz (op. 437) is. Like a lot of Strauss's best waltzes, it's not necessarily appropriate for dancing: the march introduction is very long, and the waltz itself contains so many changes of mood that you find yourself standing still and waiting in anticipation for what's coming next. I'm not saying you can't dance to it, but as David Hamilton wrote, a Strauss waltz is as much about dancing as it is for dancing.
The best article I've ever read on the Emperor is Hamilton's "The Secret Life of a Waltz," published in High Fidelity -- I can't find the date of publication at the moment, but I will. He analyzes the piece section-by-section, explaining the structure, the different characteristics of each section, the way the themes are brought together in the coda, and Strauss's tricks of linking themes together -- for example, the first waltz tune is adapted from the opening waltz tune. He also notes important details about Strauss's orchestration, in particular the use of the snare drum, which is used as much more than just a rhythm-setter; it's used for its coloristic effects (creating a military atmosphere in the march and then carrying that atmosphere over into the waltz sequences, giving it that "imperial" feeling), and a conductor who lets the strings drown out the snare drum, as many do, isn't doing justice to the piece.
Hamilton also mentions some recordings of the waltz, including those by Bernstein, Klemperer, and Furtwangler, and Reiner. Myself, I think if I could pick just one recording of this piece, it would be Klemperer's. Except for the introductory march, it's not slow, but like a lot of Klemperer performances, it's tough, unsentimental, a little astringent. These may sound like bizarre things to want in a Strauss waltz, but after all the kitschy, soupy, start-and-stop performances of Strauss, Klemperer's approach is kind of a breath of fresh air. He plays the waltz tunes more or less straight, without a lot of rubato; instead of going for a string-heavy balance, he lets the other instruments cut through and make a big, sometimes downright disturbing impact; the all-important snare drum is so loud that it can practically knock you out of your seat, and the trumpet fanfares in the coda sound like Mahler. It's not a performance that offers a lot of "charm," in other words, but it's a performance that emphasizes just what a great and original piece of music this is. Unfortunately, having said all that, I find it's unavailable on CD. A version that is available is the one by Harnoncourt, which takes a somewhat similar approach, if a bit more sentimental and without the awesome impact of that snare drum. Other good recordings of the Emperor I've heard include Ferenc Fricsay's recording with the Berlin Radio Symphony Orchestra (also out of print, darn it), and Bernstein's (out of... you guessed it).
I must admit I've never heard a Vienna Philharmonic recording of this piece that impressed me as much as these, though that may be because most of the Vienna recordings I've heard are conducted by Willi Boskovsky, a superb violinist -- he was the longtime concertmaster of the Vienna Philharmonic -- but, as a conductor, the epitome of the soup-and-swoon school of Strauss conducting, smothering everything in "traditional" rubato and equally traditional string-heavy balances. Other, earlier VPO recordings are better; Josef Krips turns in a nice performance on an old Decca LP from the '50s. (Of course, Krips was a conductor who was known for being somewhat ashamed of performing Strauss waltzes; when someone wrote an article about his abilities as a Strauss conductor, Krips was so furious that his comment on the writer's death was "God has punished him and his family for what he did to me.") But the Viennese approach to Strauss always seems too sentimental to me, oddly enough. I suppose that what I like best in Strauss is the stuff that's least traditionally Viennese about him -- he was, by the standards of other composers of Viennese light music, fairly unsentimental and blessed with a cheeky sense of humour. Die Fledermaus is probably the least typical Viennese operetta ever written, with its French-derived plot about marital infidelity, and its almost complete lack of sentimentality (the only sentimental number, "Bruderlein und Schwesterlein," is sung by a character who has zero interest in love and brotherhood and is mostly concerned with revenge). By the middle of the 20th century, however, the act of performing Strauss in Vienna became kind of a nostalgia rite, an act of longing for the Good Old Days, or as John Culshaw acidly put it, "highly coloured memories of the days of the Habsburg Empire and dear old Franz Josef." And so Strauss performances started to be souped up and schmaltzed up, becoming not so much about dancing as about the time and place in which they were composed.