im about 5'9 - 5'10 160lbs. i dont want the length to be too long. should i rock a small or medium?

I'd say medium also, if you want a baggier fit, a large probably wouldn't be a bad thing, kinda depends on your build. Either way when you put them through the dryer they are going to lose some length and become slightly tighter, not much though. I have L's and XL's and I'm 6'1 160lbish. I don;t put them through heat, just air fluff so they keep their length. The Xl's are looser and the Larges are slightly tighter. Hope some of that helps.

a medium should be good. a large fits to an ideal length IF you've got a long torso, such as myself. Anyways, my votes for the medium. Enjoy.