Unless you are already a competitive (male) bodybuilder looking for finishing exercises, both dips and decline press can be avoided for aesthetic reasons. Both these exercises target mainly the lower pectorals. Adding mass to the lower pecs can increase the appearance of "man-boobs" in an average man, even though you are putting on muscle.  Instead, do an incline bench press and cable crossovers or pec-dec, targeting the upper chest and shoulders.  This will help develop a broader, flatter upper chest that ties in with the shoulders -  a much more preferred look for guys.