I don't like spandex. I don't like synthetic fabrics. I don't like plastic. I LOVE a wool base layer for riding, though! Ibex Balance briefs and "support" bra are my new best friends. Even though I have to take them off for washing, I really don't want to. These items are light, soft, well cut, and keep me drier (while sweating) than cotton or any other fabric I've tried. It also seems they resist absorbing odor better than other fabrics. I am sold. If you are a bike shop in SF, you should carry these products. If you're a rider that's never tried wool, you should.
P.S. the balance briefs are out of stock until October 2009.