With 11,000 CDs and a very diverse music library/music genre that is too difficult to choose. I have many more great sounding (mostly uncompressed) CDs versus my 28,500 LPs to choose from (LPs can suffer from compression, vinyl problems, subgenerational mastering e.g. Angel classical records versus EMI originals, U.S.Beatles versus Parlophone, etc).
What is the VERY BEST CD album you've ever heard?
Just like with records, I came across releases on CD that were never popular, but bring lots of interesting music and so I started collecting CDs that do have collectible value for the reason of a great and rare music presented.
So far album "Sauce Hollandaise" by Ashra is on my #1 desirable list
"Best Band You've Never Heard In Your Life" by Frank Zappa is my 2nd best CD I've ever heard.