Best short-lived band?

Happy the Man

I see someone remembers Steve Still's Manassas...
The 1st double album is a great album I still have and love...
Kind of odd sound what with the 'cuban bluegrass' arrangements.

Xiekitchen, you are so right! Stephen certainly assembled an all-star band to play virtually any kind of music. That album featured standard rock, country, cuban bluegrass (Stephen grew up in central america) and great blues.
The musicians:
Stephen Stills - vocals, guitar, keyboards
Chris Hillman - vocals, guitar, mandolin
Dallas Taylor - drums
Paul Harris - keyboards
Fuzzy Samuels - bass
Al Perkins - vocals, best peddle steel I ever heard
Joe Lala - vocals, percussion

I don't think any band played so many different kinds of music so perfectly and not lose a double album flow!

A truly amazing album that for me stands alongside "Layla and Other Assorted Love Songs" and the "Are You Experienced" as my favorites.

Lust Pollution

Here are three that were around long enough to get into our heads, but went away before we could really glom on to them:
1) Creedence Cleawater Revival. You can throw out a lot of dates, but lets go with 1967 - 1971
2) The Doors. Interestingly enough, also 1967 - 1971
3) The Smiths. 1982 - 1987

I'll also agree with The Beatles nomination.