Coolest? Depends on whether the man wants to look cool or he wants the lady to.
For me, then man looks cool when he attempts ANY type of spin of more than half a turn! I enjoy a full man spin where the man turns 1.5 turns ACW when swapping sides to face instead of just 180. The trouble is that half the time I spin all over the place!
I find the ladies look good too when they spin fast and well, Try performing an arm jive turning her CW 360 on count 5 with the left hand high, keep the right connected at waist height and then push out the man's left to his left hand side, her right hand being in a nelson. Then look at the fear in the whites of her eyes and give her two turns ACW in the time normally allocated for one and put her into a normal dip to your left hand side - it does not need to be low. (see move 539 at
www.jiveoholic.org.uk). The beauty is that the man can really help the lady spin by holding her spinning hand centrally above her head.
I suppose the coolest move must be one that makes both look good. Hmmm - I will think about this.