Of course I was a HUGE fan of the Buckingham/Nicks era Fleetwood Mac, but recently went back to revisit the early stuff.  I'm not a fan of the first three albums, but from Kiln House (1970) to Future Games (1971) to Bare Trees (1972) to Penguin (1973) to Mystery To Me (1973) to finally Heroes Are Hard To Find (1974) these albums are pretty incredible.

IMHO, these era albums are overlooked/underappreciated because they weren't big commercial successes like the later works. 
I'm a fan of the original four (and later five) piece band with Peter Green, Jeremy Spencer and Danny Kirwan on guitars.  That band had an amazing sound.  I sometimes hear traces of it in the music of Los Lobos and ZZ Top.  Lots of talented musicians came after Peter Green left but I don't have much interest in what they did.  It is interesting that the name survives--the music is so very different.
I'm firmly planted in the Peter Green incarnation. But it's amazing that they've been through so many transformations, most of them very, very good, and that they continue today!
I’m with ya’ Mofimadness, all those lps you like starting with Future Games, had Bob Welch as I am sure you know. He never got the credit he deserved for leading FM with Christine McVie in the mid-Mac era. Bare Trees and Mystery to Me - not a bad song on Mystery, even the Yardbirds For You Love is great. Well recorded, layers of guitars, good vocals. He started the transition into what they became. Welch story is so sad- committed suicide so his wife would not have to care for him due to severe back issues post surgery. For me, Then Play On is a classic - serious organics while listening to that one during college. Still play the first and second Mac periods often!
kiln house was my favorite too (future games being second best)--it was the transition between the peter green blues era and the later pop stuff. danny kirwan was an underrecognized genius and his songs like "dust" and "jewel eyed judy" are classics.