THE most sonically dissappointing (lp) you own of great music?

Here's the Dynamic Range Database website link. It's surprising just how extensive the whole effort to overly compress music has been.

http://dr.loudness-war.info

The first couple of Jackson Browne LPs.

Madonna Bed Time Stories. Very very messy bass there. Extremely collectible vinyl tho.
"The Smiths" joins for poor mastering.

I'll tell you what category of LP's are dynamically compressed.  Half-speed masters.  What a total rip-off they are.  When I was young and dumb (I am now old and dumb) I collected these things basically without listening to them, and when my rig improved, I learned just how bad they are.  Except for a few A&M half-speeds, I sold almost all of mine and bought the originals of the titles I wanted.  I also bought a lot of great new hardware with the proceeds.