Anything by SBB
Anything by Gerard
Anything by Mr. Sirius
Anything by Teru's Symphonia
Anything by Ars Nova
Anything by Mike Oldfield
Anything by Renaissance (aside from Turn of the Cards)
Anything by Pendragon (aside from The Masquerade Overture)
Anything by IQ that isn't Tales from the Lush Attic, Frequency or Ever

And pretty much every other Progressive Rock band that's made a big impression on me.