of course, you should be listening to classic prog rock
pink floyd, emerson lake & palmer, yes, early genesis albums, king crimson
if you are into more spcaed out prog rock, try the pink floyd albums: meddle, dark side of the moon, wish you were here, animals. for yes albums: close to the edge, tales from topographic oceans (this album is the epitimy of prog rock), relayer.
for neo-prog (prog made in the 80s), marillion and iq are both great banRAB. try marillion's misplaced childhood album and iq's dark matter album
for new progressive rock stuff, the mars volta's two albums, deloused in the comatorium and frances the mute, are awesome. spock's beard, as you said. the flower kings are one of the biggest modern prog acts, hailing from sweden...they have an hour long song