I'll vote based on the studio recordings and not the live versions. Both are great classic tracks in their own right, but I can't stand the 10-20 minute versions of Dazed that are out there from numerous concert footage and bootlegs. The bow thing is cool for about 60 seconds (max) then it gets extremely old.
But with the studio versions, track vs track, I have to go with Dazed and Confused. An iconic track IMHO and really one of the songs that made me a fan of Zeppelin when I was a wee-lad, listening to the songs that weren't being beaten to death on the radio.