No correlation between "handedness" and preferred direction of rotation, but most people prefer to rotate anticlockwise for both spinning and jumping. Occasionally (last night, actually!) I come across a skater who wants to spin one way and jump the other, usually because they are worried about landing on the "normal" leg owing to a perceived weakness or injury. Whilst being able to spin and jump in both directions will garner more marks, it's an unusual skill and I feel it's vital to be able to spin in the same direction as you rotate your jumps. Spins, especially backspins, are the basis for all rotational jumps and, as such, really necessary if you want to be able to rotate in the air. (Check out all the training videos of the little Russian skaters and you'll see endless time spent on spinners and in harnesses for rotation practice, which needs to become second nature to them in order to master the triple Axels and assorted quad jumps that they do.)