The general range for track bikes is 165-170.
I'm 5'10 and ride 167.5 on the track. I've ridden 165 and 170 before as well, and prefer the mid range choice. Generally, shorter cranks are easy to spin at higher RPMs but give less torque to "jump" on. Longer cranks give more torque, and make it slightly easier to pedal a bigger gear up to speed, but are more of a pain when it comes to max-end spinning.
In road riding, a smaller range of RPMs is used and there's a lower top end of what you hit, while on the track where you have one gear to work with for your cruising speed and top end sprint, having a shorter crank and ease of getting to higher RPMs is more ideal. I think the fact that you have a fixed drivetrain assisting you also makes it easier to spin higher RPMs for longer, but that's ATMO.
There's a school of thought that says you should size cranks according to inseam length or some other measurement. IMO everyone has a range they can fit in, and different situations call for different sizes, but unless you're extremely tall or short, it probably doesn't matter.
Get what feels best!