Nike's relatively new line of Dri-Fit polo shirts, trousers, etc, is worth knowing about, especially in summertime.
This stuff is extremely comfortable for golf, light as a feather, and never gets sweaty. The polo shirts are good for tennis, and do not get heavy with sweat. Polyester, but nothing like what one thinks of as polyester.
Their Tour Pleat Golf Pants are also the most comfortable travel pants I have ever worn.