Rare Earth - Live.
If I'm honest, I preferred the lengthy improvisational parts on that to DP's Made in Japan where I always thought that the 20 minute version of Space Trucking overstayed its welcome. But I never minded the 25 minute live version of Get Ready, any other version just doesn't sound right.
(albeit a very short version)
And though I never was and never will be a Zep fan, I thought (and think) that Physical Graffiti presented an interesting and eclectic mix of music. It is in fact my favourite Zep album.
Talking about drawn out songs on double albums: Honorary mention must be made of Loggins & Messina Live album and especially "Vahevala" on it!
(a much later version, but still nice)
Uwe