Peter Green (Greenbaum) Fleetwood Mac. This is the original Mac, repeat original. Grab a compilation with the following.
-Need Your Love So Bad
-World Keeps Turning
-Man of the World
-Jumping at Shadows - a superb rendition of Duster Bennet's tune
-A Fool No More
Finest blues singing and guitarist of all times, Peter and original Mac got it right!