Personally. I think we're doing an apple and oranges comparison here. While the two bands may have shared an era, they are different styles of music.
If forced to make a choice though, I gotta go with Zeppelin. AC/DC, while a good time band, was a bit simplistic and meaningless; lyrically not much better than the ghetto gangster rappers of today.
Zeppelin was far more complex with their composition and arrangements.
I could take or leave Plant, but I don't think any band could ever match the Page/ Bonham combination and creativity.
Unfortunately, as mentioned above, Stairway saturated the airwaves and kind of burned-out many people on Zeppelin, as well as detracted from some far superior but less-played songs (Kashmir, Babe I'm gonna Leave You, Over the Hills and Far Away, The Immigrant Song, Thank You, Travelling Riverside Blues, Four Sticks, Tangerine, Gallows Pole, No Quarter, The Battle of Evermore, When the Levee Breaks, and Going to California).