My favorite example of Led Zeppelin improving on a blues classic:
http://www.youtube.com/watch?v=DqDLVR2I5QE
But at least Zeppelin didn’t try to pass this of as “original” material the way Elvis did with “Hounddog”.
Big Mama Thornton’s song was a big hit on the R&B charts before Elvis; I am sure there was no confusion over who did the original there.
Elvis did employ a good stable of songwriters like Mac Davis, Ronnie Milsap, and Leiber and Stoller.
But I loved that Zeppelin song; good stuff. Going to the theater on Oct 17 to see the iMax version of the 02 reunion show, Celebration Day.
Led Zeppelin's version of "When the Levee Breaks" is certainly different from the original. However, it fails to capture the pathos of the original, which was likely inspired by catastrophic floods of 1927 and 1929 in the lower Mississippi Valley.
The original version is unavailable on Youtube, but I found it on a Chinese site.
When the Levee Breaks--Memphis Minnie & Kansas City Bob, 1929
Although Willie Mae Thornton had the original version of "Hound Dog," as far as I now, Freddy Bell & the Bell Boys was the first act to perform the arrangement which Elvis Presley used. I like their version better than his.
Hound Dog--Freddy Bell & the Bell Boys (1955)