Rush's synthesizer sound hit its zenith (or its nadir, depending on how you feel about that sort of thing) with their 1985 album Power Windows. While older Rush albums used the synthesizer primarily as a padding instrument, on the lead track "The Big Money" it takes the lead with heavy, bright stabs and sequenced riffs.
"The Big Money"'s video is notable for two things. One, believe it or not, these computer graphics were state of the art (it had only been a few months since Dire Straits' "Money for Nothing" broke new ground for digital animation). Two, Geddy's mullet makes him look like a cross between Pippi Longstocking and a poodle. Aren't you glad the 80s are over?