i'd have to say 'ramble on' is in my head a lot and awesome but not my favorite either. maybe 'ten years gone'.
i always think when i listen to rock music in that era it still sounds black, rock and roll. like now rock music has morphed completely away from those origins. led zepplin you can definitely hear southern blues, maybe even funk in their music.
rock music is terrible these days. i guess because it sounds very pussy and rhythmless.