Black Sabbath - Paranoid
A legendary riff, very fast on the drums but not so much on the guitar, you'll find in the first bar a rhythm that has been used and abused by all the greatest rock bands. Beware of the appoggiaturas that are there to complicate things a bit, otherwise it would be too easy! And in the second bar, a little melody on the E minor pentatonic, played and written in succession of hammer-on and pull off, but you can pick all the notes if you want.