Hi JLS,
Well, tbh I`m a little confused by your question. The 24 Preludes and Fugues are pieces for the piano, so there is no conducting going on. It would be a big surprise to me to find a recording of Gergiev playing them; although he plays the piano, I think he`s mostly a conductor. Unless there is another 24 preludes and fugues by Shostakovich that I am unaware of...
I`m not a Shostakovich expert; I am more familiar with his symphonies (love the 5th) etc. That being said, the Nikolayeva recording might be most interesting from the historical perspective- Shostakovich wrote the piece for her. The Ashkenazy has been favorably reviewed by many, and there is also the Keith Jarrett version which is liked by many as well.
If you like, let us know which one you pick, and what you think about it!
PS Hope you get your avatar working soon.