Like everyone else here, I would say Peyton, Reggie and Doug are definitely on this particular Mount Rushmore.
Witten is definitely working his way into the conversation, but I don't know if he'll ever quite get there. I kind of think Witten belongs more in the same category with guys like John Bruhin, Deon Grant, Dale Carter, Carl Pickens, Chad Clifton, Bruce Wilkerson, Tim Irwin, Raleigh McKenzie, Willie Gault, Tim McGee, Stanley Morgan, Hacksaw Reynolds, Chuck Smith...probably a few others I'm missing.