What are some good unpopular classic rock songs?

So I'm going on a road trip real soon and I want to get my iPod loaded
up with a ton of good songs... I'm a huge classic rock fan and I have
pretty much all of the most popular classic rock songs and I have
like, everything by The Beatles... but yeah, I was wondering if anyone
could suggest some good old rock songs from the 60's, 70's or 80's?
something that isn't very well known, because if it is, I probably
already have it. thanks!