Hard Rock: when it comes to this genre, the mind immediately goes to Led Zeppelin and Deep Purple (along with Cream and Free)... I would like to propose a few examples of lesser-known bands or those not directly associated with the genre.
17 - Carry On (Live)
This is definitely the most "hard" track by CSNH. Of course, considering it Hard Rock is a bit of a stretch, but it's also a tribute to Crosby...