Crank arm length is somewhat dependent on leg length/cadence (and other factors) but generally sprinters use shorter... if you do a search of this site e.g. Form and Fitness you will find articles or links to the info you need.
It has been awhile but when i was racing 165 was the standard, I know some kilo & pursuiters would go a little longer but generally it was just easier to go with 165 for everything.
I am actually 6ft 1in tall with a long inseam and when i started riding road i did a professional fitting and started using 175. I ended up always grinding too big a gear. Then i went back to track & found my spin again using the 165's. When i went back to the road i switched to 170's, even for road racing. I feel like it is easier to accelerate the shorter crank(turning smaller circle) and i don't notice any loss of power on the climbs. I feel like i have just as much leverage.
Bottom line you get a better spin with shorter cranks and once you become acclimated to them you will love them.