Deep Purple is one of those bands who I feel is grossly underrated in the US. Sure, most people know Smoke on the Water and Highway Star (thanks to Rock Band), but few know more than that. Oddly enough, they are huge elsewhere in the world and within the hard rock/heavy metal community they are often cited as huge influences on many of the artists/bands that followed them.
Here are a couple of my favorites. Especially pay attention to the last video of Child in Time if for no other reason than to watch the lack of animation in the audience. I don’t know how anyone can appear so indifferent to a band rocking out like that. It cracks me and Leah up every time we watch it.