Your favorite but unknown

I know there are probably a good sized music collection that is shared by a lot of us here, but there must be some favorites that some of us have that no one else knows exists. Thus the question:

What is the one unknown LP, CD, 8-track in your collection that is indispensible, but that no one else knows about?

My favorite unknown (by most people anyway) would be Steve Taylor's LP "I Predict, 1990."

It is so good, but I doubt that more than a handfull (and I have big hands) of us on AudiogoN have ever heard of it. It contains lots of tongue-in-cheek humor, insightful lyrics, pot-shots at some well known and maybe respected institutions, all wrapped up in a good recording.

Now what are yours?