I can't say that anything jumps out to be a favorite all time but I'll list a few of my favorites.
Alan Parsons, I Robot, most of his music is good
Heart, Little Queen, some of the best female rock vocalists of all time
Cat Stevens, Tea for the Tillerman, all Cat Stevens LP's are good
Emerson Lake and Palmer, nearly all of their stuff, good live too
Yes, 90125 but most of theirs are good too
Jethro Tull did some great stuff and was great live before Ian got old
Fleetwood Mac, Rumors, also great live
Kansas, Leftoverture, I'll agree, that was a good one
Pat Benatar, one of the best female vocalists to ever sing rock music
Sarah McLachlan, great voice, great pianist and writer
Bach organ music, Virgil Fox played it better than anyone I've ever heard and was amazing live
Davey Spillane, kind of celtic/jazz/rock played bagpipes and various instruments in Riverdance, very talented also great live
Lot's more that I listen to but these all stand out for me as some of the best performers that I ever had the pleasure to hear.
Bill