Often times when 'the Greatest Bands" are mentioned people are referring to the bands overall contribution to the world of music and such, but this question is much different because even great bands are often not diverse or versatile enough, even if they last a long time. My vote goes to FLEETWOOD MAC and for several reasons....

The biggest thing that FLEETWOOD MAC has/had going for it is the different lead singers, since the band was initially a blues-based group in the late 60's and then transitioned into a more softer rock group during the 70's with the talents of Stevie Nicks and Lindsey Buckingham in the group. The different stylistic shifts always gave this band an edge and having a variation in their lead singer, plus different song-writers within the band they kept evolving over time. Though it's easy to say that this bands strongest point was during a 3-album streak starting with the 1975 self titled album followed by RUMOURS and then TUSK, it's hard to argue the vitality of these three masterful albums. The 80's proved to be a difficult time as the band struggled with the solo-careers emerging from Nicks and Buckingham, though even TANGO IN THE NIGHT from 1987 had a few decent hits, which also sounded more like what Buckingham and Nicks were doing on the side, which was a more pop-oriented rock. Buckingham's guitar-style is really what helped give the band it's uniqueness on songs like BIG LOVE, BLEED TO LOVE HER, LANDSLIDE, etc.

It's probably fair to say that this band has changed about as much as YES and is quite a different band in many regards to what the initial concept was, same goes for bands like PINK FLOYD, but versatility is what really helps make FLEETWOOD MAC one of the most important bands, even if they are not 'technically' still together. 2003's SAY YOU WILL proved to be a melting pot of the bands coming together each person bringing their own material and again joining together to create a really mixed album overall, but again track to track the band is different in many regards, yet still have the signature sound and style that can be attributed to FLEETWOOD MAC.

I can't think of too many other bands that have lasted this long and have brought as wide or a range of material and has been popular with a large portion of it.

So what other bands come to mind when you think of versatility???