See the "wool weenies" thread.
Merino wool is non-itchy and as stated above, wicks sweat, doesn't smell. I've worn merino hiking shirts very successfully. While I don't wear wool for cycling in the summer, I do know those who do. I have wool jerseys for cooler weather.
Base layers? They really save you in the bridge seasons, especially spring, where rides start cool and often ended up warm. The right base layer can work in a wide range of temperatures. I have Craft base layers in short sleeve, long sleeved, and sleeveless. I also have a couple of Smart Wool LS base layers that I love for nordic skiing and really cold rides.
2015 Trek Silque SSL
Specialized Oura
2011 Guru Praemio
Specialized Oura
2017 Specialized Ariel Sport