...in my opinion, anyway. Glad to hear yours in the comments (click on the category, "Great Moments in Obscure Rock 'n' Roll" [in which this post appears] to see this year's selections from which to choose).
Here's my top five:
Blodwyn Pig, "Same Old Story," 1970
The Damnation of Adam Blessing, "The Last Train to Clarksville," 1969
And a few runners-up that could just as well have been the top five:
Blonde on Blonde, "Conversationally Making the Grade," 1969