|Instrument||Guitar, Backing Vox|
Not necessarily in the following order:
Steve Vai for "Ladies Nite In Buffalo", "The Crying Machine", "For The Love Of God" and "Touching Tongues" and because whether you like the music or not you should at least appreciate his skill and showmanship and because after all he is the "Genius, master of the space-age guitar" according to Brian May (and who am I to argue!), which leads me to:
Brian May for some of the best riffs like "Tie Your Mother Down" "It's Late" and "Dead on Time" and without doubt the best harmony guitars e.g. "Good Company" (check it out for the ukulele solo!) and most tasteful guitar work (that note on "It's a Kind Of Magic")
Alex Lifeson, for "La Villa Strangiato" "The Trees" "Time Stand Still" and introducing me to the concept of chord riffs ("Freewill")
Edward Van Halen, for "Cathedral" "Ice-cream Man" "Eruption" "Dance The Night Away" and rhythm guitar work on countless others.
Joe Satriani for "Flying in a Blue Dream", "Satch Boogie" "I Believe" etc.