Mozart Piano Concerto 21.

Curzon with Kubelik, thats the one.

Artur Schnabel, London Sym. Orch, sargent cond.
masterful, artful playing.

Lipatti...no question about it!...second option Curzon...

At the risk of sounding out of touch, what is the panel's opinion on Vladimir Ashkenazy's recordings on Decca ? The recording is not perfect (early digital), but I really like his flair. Am I missing something ? I'm no classical buff, but it sounds like a good performance to me.

This is not an easy question to answer. It is so subjective. Besides the "quality" of the performance and the sonic quality of the recording, there is the matter of modern vs. "original" instruments.

Many of the recordings mentioned above are on modern instruments with modern-sized orchestras. To that list, I would add:

Maria João Pires. Chamber Orchestra of Europe, cond. Claudio Abbado (DG, 1995)

For recordings using "original" instruments, etc., the definitive recordings (in my opinion) are by Malcolm Bilson, who has issues the entire cycle on CD. For No. 21, see:

Malcolm Bilson. English Baroque Soloists, cond. Gardiner (Archiv, 1987).