Martinon's Debussy goes to my desert island.
Discs 1 & 2
Ashkenazy sometimes gets criticized for bland, right-down-the-middle interpretations -- and not just with Rach. Sometimes I can hear that, sometimes not at all! . . . I happen to love Ashkenazy's recordings of Rach's Preludes, Op. 23 and Op. 32. But I've not heard much else of his Rach solo-piano recs.
I have Ashkenazy's Rach PCs with Previn & the LSO -- I think they're OK, but not among my favorites. (I've never heard the Ashkenazy's PCs with Haitink & the RCOA that are in the this set.) Actually, my favorite Ashkenazy Rachmaninov PC recording is the 3rd with Ormandy, originally released on RCA in the mid-70s: