For the people that have been playing for a while, this might be a distant memory, but do your best to dig it up!
First legendary drop was the Hammer Jammers pants off of a regular Herald of Pestilence in Fields of Slaughter Act III Hell mode.
First set drop was a Natalya's Soul boots when I popped a vase in the Great Span in Act IV Inferno (preparing those ghost farming exploit runs, remember those?).
Edited by Jaetch, 23 November 2012 - 05:25 PM.