Rhone Sentry short sleeve shirt (was $68, 29% off plus free shipping with code GQSENTRY)
The Goldilocks of workout shirts, this one clings in all the right places (around the biceps, for example, so that the sleeves don’t ride up and down) and none of the wrong ones (the shoulders, the armpits, and—[shudder]—the gut). It’s breathable enough to prevent soak-throughs, but not so thin that a brisk day will highlight your nipples to everyone on the track. The v-neck styling is a subtle way of differentiating itself from the crew-collar competition. The best part, though, is that the fabric is infused with little bits of gold, which the company says delays the onset of that dreaded perpetual funk that most every other workout shirt succumbs to eventually.