Pictures of Matchstick Men.
I probably heard this song first as a cover by Camper Van Beethoven (my second favorite Beethoven!). My sister listened to a lot of Camper Van Beethoven and I certainly heard it first thanks to her. They do an excellent version, with a violin doing that amazing guitar riff from the original.
Ozzy Osborne and Type O Negative did a version for the Howard Stern movie. I like that one as well.
But the original?
Fucking hell. That guitar riff is amazing.
If you were thinking, I had no idea who did this, then Status Quo is probably one of the best bands you've never heard of.
Check out Ice in the Sun (which might be better than Pictures, even) and Technicolor Dreams:
They transformed a little later into more of a 70s/80s rock band than a late-60s psychedelic group. I just wanted to highlight some of the early stuff I like so much.