I still think the Deutsche Grammophone/Steinberg-Boston Symphony version is the best, but I'm an old fart and that may pre-date most of you:
I've had the vinyl since 72, at least.
The CD version gets some excellent reviews - it's one of the quickest at 46 minutes, even though Holst would do it at 41, supposedly. At least, that's in one of the reviews I read. Today they package the CD version with Steinberg's rendering of Zarathustra - not too sure about his version of that one, but the Planets is the best, IMHO.
My friends and I always used the DG vinyl version of the Planets as our definitive equipment tests. I can remember listening to this while stacking Advents fed from a Sherwood S8900A and a Benjamin Miracord with a fat Empire cartridge. One buddy had a Dual and a Sony 7065 with Advents (that's how we got 4 of them to try the stacking). Another had a huge Kenwood reciever and Audio Analyst speakers with one of the first versions of the SL-1200, I think. Maybe this is an AudioKarma post?