I rarely leave home for any kind of trip (racing, training, holiday, whatever) without a Patagonia top, capilene or merino.
http://www.patagonia.com/us/shop/mens-baselayer?k=1D-6M
Favourite capilene is the lightweight, silkweight great in warm weather.
Expensive, but bomb-proof build quality; I have a heavier capilene long sleved top which is over 10 years old, barely a mark on it, used week in, week out during the colder months.