My kinda music
1) Russian National Orchestra under Pletnev is really good. You can get all six numbered symphonies plus the Manfred for about £20. This is an easy first recommendation, the 6th is demonstration quality. The finest modern version IMO.
2) The classic version is Mavrinsky with the Leningrad Phil. This is perhaps the most idiomatic interpretation, "the Russian sound", but these are old remastered recordings and you might be disappointed with the sound. The performances are peerless.
3) The Muti versions are also very well regarded and are very good value.
4) The Penguin Guide (which is a bit out of date) recommends the Jansons, Oslo Phil, version. I haven't heard it but they give it a Rosette, which is their top award, so it's worth trying.
5) The greatest bargain is Litton, Bournemouth SO. This is a really top notch version and you get some other stuff too in a 6 CD box for less than £15. I play this a lot.
6) There are a variety of Karajan versions and I always get confused about which is which and anyway he is erratic IMO, sometimes superb and sometimes poor. However I don't think you need to worry as the 5 above are better in many ways.
Chris