Basically, all their albums up to Raising Hell. With those three albums, they not only changed the whole approach to rap music, but became superstars in the process. Particularly memorable singles include:
"Hard Times," their very first single that set the standard for their early output.
The legendary rap/rock mixture "Walk This Way" featuring Aerosmith.
"Rock Box" see Run DMC rock harder than most Hair Metal bands. "King Of Rock" goes even harder.
Everyone and their mother knows the words to "It's Tricky."