I dont really have a favorite punch combo. when sparing I usually go with my with the flow and do what ever. when I fall in to combos I tend to telegraph what I am throwing. usualy use the jab to judge the distance then throw a one two and other than that i do what opens up.
as far as kicks go I like to throw a repeated right round house changing levels. for instance Low Low mid, low mid low, low low low, mid mid low.
however my favorite thing to do is to raise my left knee fainting a crescent kick then coming around with a spinning back kick or spinning side kick.