The two bands are really two different kinds of music.
Usually people would compare Led to, say, the Who
(while Pink Floyd can be compared to Alan Parsons
Project).
Though I generally prefer the latter style, I will go with
Led Zeppelin. They have just way too many kick-ass
songs ("Kashmir", "Ramble on", "Babe I'm gonna leave
you" being their three best, in my opinion).
Pink Floyd I only basically like "Hey you" (sad song).