Or, to word it more intelligibly, can people suggest what a good collection of significant versions of Mahler's 9th should include? I've been getting quite obsessed with it lately, as indeed one might, and what I have at hand are a Karajan/BPO version, the recent Rattle/BPO version and EMI's re-issue of the first recorded version, Bruno Walter/VPO. The differences are remarkable, especially between the Karajan and Rattle versions which seem to be as different as humanly possible while still playing the same piece of music. Where Karajan's version is lyrical and glowing, Rattle's version can seem almost brutal at times. On the other hand, Karajan seems to smooth over the jagged edges, for instance in the Rondo-Burleske he seems to thwart the burlesque aspect altogether. The Walter version suffers on account of the sound - although what I can hear convinces me to acquire one of Walter's later re-recordings of the symphony.

Still, each version I've heard has only helped whet the appetite for more. There's a version conducted by Barbirolli in a record shop nearby that I will probably acquire shortly, but what else is out there that one should have, bearing in mind that I'd like to have a good survey of different approaches rather than a lot of versions that follow in each other's footsteps?

Oh and did you see this recent post?

http://r3ok.myforum365.com/index.php?topic=137.msg106316#msg106316

I didn't know of that Ancerl recording either and it looks as if I'm going to have to add it to the list of 'must haves' that this Message Board keeps throwing up. 

The Mahler 9 recordings that are particularly important to me (and they are indeed very different in their respective approaches) are

Berlin Philharmonic/Barbirolli
New Philharmonia/Klemperer
BBC Symphony Orchestra/Maderna
and, yes, the Berlin Philharmonic/Karajan which, despite reservations, definitely comes into the category of 'significant' recordings of this extraordinary work.

I'm still very fond of the Chicago Symphony Orchestra/Giulini recording though I know not everyone is. I suppose it has to be regarded as 'of its time', in particular the amount of vibrato in the strings that he employs, but it is an achingly beautiful elegaic thing even so.   

There was also what I regarded as a very fine recording by Rudolph Kempe, which again took a very distinctive and original view of the work to set alongside the others, but it seems to have gone missing from where I was expecting to find it. I can't now remember the orchestra. 

I'd like to add the Live in Berlin recording (15 November 2006) by Staatskapelle Berlin, conducted by Daniel Barenboim, revealing all the surprise and contrast in the 9th.    Warner Classics 2564 64316-2

I posted on this recording last autumn and was most gratified when one of our most eminent musicologists on this board,  e-mailed his personal set of notes on the work.

 Are you familiar with Alan Bennett's play 'The History Boys'?   The rudimentary philosophy of Rupert, the Headmaster, was "Pass it on".     I think that my contributor would be content for me to do this, in turn, if you are interested. 

I see that neither Boulez nor Abbado have been mentioned yet...

Each time I acquire a new recording of this work it becomes my favourite for a while because there's a new angle (or indeed many new angles) from which to appreciate it with renewed wonder: the last two have been Barbirolli and Maderna. The one I "keep coming back to", though, is the one in my head which will never actually find its way out (except in somewhat sublimated form). That's rather self-indulgent and unhelpful, I know, so I'll just say that Maderna's recording has been the one which has had more impact on me than any other for many years.

I haven't nine to recommend.  Your original list includes Walter, both of whose commercially released versions are to me in classes of their own.  My reasons for saying this?  Largely the close relationship between Walter and Mahler, pupil and teacher, the fact that Walter gave the first performance and understood the music as though he had written it; the absolutely idiomatic grasp of how Mahler should sound, linked to the ability to extract deeply felt performances from his orchestras, the VPO and Columbia Symphony - a group of Hollywood studio musicians who had never heard let alone played the piece before (the CBS stereo recording) and the wonderful humanity of the readings - nothing empty or for effect and all deeply felt. 
I am sure others have compelling reasons for their first choices but for fifty years, to my ears and emotions it has been Bruno Walter that gets me closest to this piece.

Along with the 6th the ninth is my favourite mahler symphony although dont know who to choose recordingwise - i only know Tennstedt and Karajan versions
My favourite live recording was surprisingly Boulez at the Albert Hall some time back - i say surprisingly because always had impression (false) that his interpretations were kind of cold - but this performance was red hot and had me in a sweat !!!