My usual first reaction, when asked to name my favorite song of all time, is When the Levee Breaks.
I have a friend who said that most music lovers either love Zeppelin or the Who -- but not both. But that doesn't apply to me either.
yes, i love Levee too...but i could never pick and choose among Zepp tunes...i just love them all. they are simply epic.
as for your friend, that is interesting...i always heard it as the choice was most people felt that way about The Who and The Stones...after all, they came up at the same time...they were both the rabble rousers who were trying to fill the gap after the Beatles. They were both naughtier than the Beatles. The Who were a "Mods", while The Stones were more R&B, though the Who later became full on rock and ultimately much harder than the Stones, who remained in R&B and then went more into Soul towards the end.
The Who and Stones were generally the rivals...The Stones 1st Album came out in '64, and the Who's 1st album came out in '65.
Zepp did not release their first till 1969.
for me, LZ is my favorite, but i really love the Who and the Stones as well...just not as much as i love Zepp