What CDs to buy

For the most part, CDs were mass produced in many countries. At the peak of CD production, there weren’t many Pop, Rock, Country releases that stood out in terms of sound quality. High quality was the norm for classical and jazz. There were some great albums that should be in everyone's collection such as Pink Floyd's Dark Side of the Moon.

After the mid 90s til present, record labels began to remaster the original CD releases, and started a wave of terrible sounding discs. Read about the Loudness Wars.

If you want to start listening to jazz or classical, @jasonbourne52 made some great choices.

There are some small producers of high quality CDs and records of  different genres. 

Google "Analogue Productions" and "Mobile Fidelity."

XRCD’s …. Step- up in mastering from ordinary redbook cd’s

go browse DISCOGS and ELUSIVEDISC , especially for their Various – Best Audiophile Voices series 

https://elusivedisc.com/music/digital/xrcd/

@akg_ca 

Elusive Disc +1. Good pricing for XRCD.

Are the Redbook releases remastered for audiophiles?

The Blue Note XRCDs are outstanding. I was just listening to Hank Mobley's Soul Station, and it is superb.

Also, it is well known that some, but not all Japanese remasters are excellent. They can be expensive, but in my view worth the retail cost in at least some cases, I believe. For example, I grew up on '70s funk and soul, and of course there were plenty of less than stellar recordings. But the Japanese remasters of, for example, the early albums  of Tower of Power and Earth Wind & Fire, are really excellent.