Booker T and the MG's "Green Onions" is an all-time classic. It's 12-bar blues rhythm, clean Hammond organ lines, Steve Cropper's surf style guitar lines, Al Jackson's drumming and the song's perfect structure are so distinctive and memorable that the song is etched in our brains and an iconic moment in American culture. It's damn near our Beethoven's 5th. You almost forget it is an instrumental -- and wouldn't even the best lyrics and singing merely get in the way?
The title came from a cat named Green Onions in the cartoon Green Badger; the cat's style of walking is said to have inspired the distinctive organ line.
Here's a great live version that appears to be from a TV show:
And then there's this one from 1966 on the TV show Shindig: