I resemble this...
For me, a wool base layer top is the best at avoiding the "cold and clammy" feel at lower temps, so that's what I wear probably 6 - 7 months out of a year here in NorCal and the Sierra. That chilling effect doesn't bother me when it's warm out, in fact I welcome it, so I wear synthetic tops in the summer though.
Wool is somewhat fireproof vs synthetics which turn into napalm at a certain temperature. Which is probably more relavant than people think. I have had jobs that banned synthetic clothes but if you ever find yourself in a situation where you need to warm yourself and dry your clothes by fire, wool is going to dry faster and less likely to turn into a blob of melted plastic.