1975-1982 for me! To be fair though this is based purely on only hearing the original lineup on a live c.d. I own with them but based on that c.d. it's just not for me. I agree with the ones who say that the member changes really fleshed out the band and gave them more of a unique sound. Coincidentally, the first Fleetwood Mac c.d. I ever bought was "The Dance" which was also a live album as all of you surely know. So just putting those two c.d.s side by side would make the decision alone for me!