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.