Tough assignment - recommending a 'great' recording of a great performance for someone who has a great audio system, with no clues as to what aspects of this piece, or Chopin for that matter, are important to him. Only an idiot would respond! Well here goes -----
Assumptions - because you ask I'm presuming you are looking for a 'dreamy' version and one that is clear in tone. Because you are not my mother I took out only 8 different versions, including 4 by Chopin specialists, which are all in print, and some of which are in two CD sets. If you want more, Google or get out the Guides in print or on the 'net which have all of the old(er) ones. :-)
I found 2 versions that might fit, 1 for sure. Angela Hewitt "Chopin Nocturnes" on Hyperion, a two CD set. This is almost as romantic as it gets, I think. And it should sound great on a hi-res system. And you also get a good set of Chopins Nocturnes as well.
Now if I only had to consider style, slow, dreamy romantic stuff, I go for Jon Nakamatsu on Hyperion BUT the recording is a tad resonant which will show up on your system. This is only one cut on the CD. The companions are much more diverse. I like it quite a bit. In fact a lot.
A little less 'dreamy' perhaps, but a good compromise in style (not too aggressive - common with many Chopin specialists) is Howard Shelly on Chandos. Probably a good choice for someone looking for a very good recording in a style that is neither aggressive nor too slowly paced.
If you want something a bit faster, Horowitz's recording on Sony is quite nice.
FWIW, my first 'go to' for Chopin in general is Ohlsson, if for no other reason that he is Polish and plays a Bosendorfer Grand Imperial. If you like this instrument his Impromptus 4 comes in a two CD set including the Polonaises and his pace is on the slow side.
Then there is always Rubensteins which continues to recieve universal acclaim.
Probably didn't help you much did I........
