It's highly individual, depending on your riding style and your physique.
I have a CBR1000rr, and set up my CB450 to mimic the riding position.
Many people make one of two mistakes: clip ons or other low bars, and stock pegs, or just as bad, placing the rearsets in the passenger peg spot (easy way out, as far as mounting). Neither works well in my opinion. Ideally, for most people, your rearsets should fall somewhere between the rear peg and front peg locations, if going with clip ons.
1974 CB450, 2006 CBR1000RR