Well, since Fleetwood Mac {1967 - } happen to be one of my equal favourite bands...
"Rumours" is not only my favourite Fleetwood Mac album, but probably my favourite album in general.
But the 1975 'white' "Fleetwood Mac" album {as Christine McVie called it} does contain 'Rhiannon', 'Say You Love Me', 'Landslide', 'I'm So Afraid' and 'Crystal', so I guess it comes in a close second.
If I had to name my favourite songs, the list would be so long it would just annoy everyone!