2&3 are the famous biggies, yes, but I would hate to be without a copy of the fourth... after I heard the amazing recording of it by Michaelangeli/ Gracis (on EMI coupled, coupled to an equally legendary Ravel Piano Concerto). For Ashkenazy, I understand that 2&3 are his best, so I would recommend just getting those, then furthering your Rachmaninoff concerto cycle with other recordings, such as the Michaelangeli. And if you do feel like going on to the 1st, I'm sure there's an excellent, more authoritative, single version of that as well. This may take more time... may cost a little more... but more fun searching them out, you'll have the best of each piece, and you won't get saddled down with pieces that you don't want (The economy of boxed sets is kinda lost if you don't listen to half the recordings in the box!... The complete Mozart Edition?? AUUUUUUGH!!!!) But DO make sure you've got the Michaelangeli Rach4/Ravel... Perhaps the Ravel has been surpassed by the new Zimmerman/Boulez (IMNSHO, it HAS... WOW!!!), but heck, ever since I heard M's Rach4, it's been my favorite of the Rach concertos! Albie