Your favorite prog rock music? ?

I used to be a real maven on the subject-I've aged and gone in different directions. I can, however, give u some ideas:

Yes-Close to the Edge and Topographic Oceans (Latter is a controversial choice as many hate it)
Genesis-Selling England (A killer great work)
ELP-Tarkus (Most would say Brain Salad)
Hawkwind-Space Ritual (Trust me, it's an original. By the way, "do not panic".)
Pink Floyd-Meddle
Tull-Thick as a Brick (It's progressive, I guess, but more in the "art" camp)

This is a decent start.

Let me add to my list the following:

King Crimson-Starless and Bible Black (heavy)
King Crimson-Larks Tongues (really heavy)
Strawbs-Hero and Heroine (folky elements in this band add character to the prog feel)
Eno-Another Green World (really more "ambient" than prog)
Moodies-Question of Balance
Nektar-Remember the Future