http://www.cptips.com/crnklth.htm

For FGs I like somewhat shorter cranks than is normally recommended for a geared bike. For example, I'm barely over 6' and I normally ride 172.5-175 mm cranks on road bikes and on FG bikes I ride 167.5-170 mm cranks. Track riders, in general, use shorter cranks that road cyclists. The shorter cranks avoid pedal strike and allows one to sustain a higher than normal cadence. This normally isn't a concern on geared bikes, since you can always shift into a higher gear when the cadence gets too fast, but on a FG, you are often stuck pedaling at very high cadences, especially if you ride hills.

At your height, I would probably choose 165s, but a few mm variation in either direction isn't going to make that much of a difference.