I don't think there's much debate as to where he ranks among the greatest welterweights of all time but where to you rank him among all fighters? Above/below Fedor? Above/below Spider? Above/below Jon Jones? GSP is the only top fighter to have avenged all his losses (never losing a rematch or rubber match) and to have beaten all of his opponents at least once.
I still put him below Anderson and Fedor. Jon Jones' career is way too early to tell and place him up there, but when all is said and done, I could see Jones being #1. GSP right now is probably 3rd for me.