I had a time when I listened to CDs that were ripped and then compressed to 128kbps MP3. One day I had the CD and just listened to it straight on the computer through headphones and was blown away by how much I was missing on the MP3. My take is 192kbps MP3 is a lot better and 320kbps is basically transparent.

I got a really great set of Yamaha speakers at our reuse center and, similarly, found a whole new world in some recordings (everything by the Super Furry Animals except their first album) but then found others (anything by Foreigner) sounded just the same as they always did on FM radio.

Even at 128, not many people can pass a double blind test. And yes, almost everyone struggles once you get somewhere in the range of 256/320.

Doing a bit of research, it looks like a majority - ~60% across studies - prefer the better quality in double blind tests at 128. At 256/320 it drops off dramatically, yes.

I know I personally have sought out better copies of some songs because the high end sounds awful, witch each hi-hat splash being a crinkly-codec failure.