Clothes engineered to minimize stank are indeed magical, but unless you're into eye-searing moon fabrics, it's hard to find any that could be considered casual. Instead, pull on the dry coolness of Sameunderneath.
Seattle-based Sameunderneath cuts eco-conscious gear from a proprietary textile fortified with bamboo -- God's own "porous micromaterial" that's also naturally anti-bacterial, and as breathable as a Wiffle Ball gag. SU's subtly-military jackets, tees, and long-sleeve shirts remain odor-free even if you bathe with the frequency of a tree-bound arboreal rights protester. Better, their bamboo-cotton blend results in luxuriously supple clothes, with a waft that surpasses cotton-cotton in thickness, softness, and sex-soaked panda magnetism.
For travelers/suitcase'd couch-surfers, the bamboo also makes SU's gear self-drying and wrinkle-proof -- just lay it flat, and the moisture/creases will disappear. The clothes are so low-maintenance that decked out exclusively in the stuff, you'll never break a sweat or lose your cool -- even though you're naked from the waist down.