The entire "Best of the Guess Who" is great, esp. "Side 1" (yeah, albums -- remember those?) "Undun," "These Eyes," "Laughing," "American Woman," etc.
"Star Baby" is a great -- and lesser-known -- Guess Who song that's really good.
"I'm Scared" is a great cut off his same (first) solo album that featured "Stand Tall." The "You Ain't Seen Nothing Yet" duet with his old Guess Who bandmate, Randy Bachman (who had a HUGE hit with the song when he was with BTO) is cool. His second solo album was okay, but nothing great.