Very interesting thread. I don't do much critical listening (and have never had the system to warrant it!), but have always been struck by discs that sounded particularly good. About a year ago, I started making some upgrades and found that, while some things sounded amazingly good (Jeff Buckley and the last couple of Radiohead and Wilco albums, for example), the distance between good recordings and bad was substantial -- so great that some music I like was hard to enjoy (Squeeze reissues, Oasis, Husker Du). My current system has closed the gap. The good stuff (sound quality wise) still sounds good, but the bad stuff is way better. I can still hear the difference, but it's not distracting.
What of your CD's have good sonics?
I have been amazed at the number of CD's are so bad I can't bare to listen to them on my system. It seems like over half are difficult to listen to. Vinyl seems about the same. I have been buying some classic rock albums from a local used record store and am surprised at how many of them sound bad. Most of the jazz albums I buy are usually quite good. How is it with you guys?