If you are taking the wingback position out of the equation, Westerkamp is in the conversation as the best ever. Otherwise, Johnny Rodgers would like a word. So would Fryar.
If you compare him only to "Split Ends" from past eras, Westerkamp holds up pretty well - although guys like Tim Smith, Frosty Anderson and Jon Bostick would have caught an awful lot of passes in today's game.