bnguyenSince you're 6'0", I'd say go for the S and have it shrink over time; i like to wear mine layered so i like some room; other folks like it to be really fitted. It's ultimately your call.
bnguyenI'm 6ft with a 37 inch chest and my small is bordering on too short length-wise. If I want to cover my belt. Especially since it doesn't close at the bottom, I'd recommend getting Small Tall. Shrink on mine seemed to have happened only width-wise for some reason.