A sports bra is THE most important piece of clothing for female runners. Whether small or large chested, optimal fit and support make running not only more comfortable but also healthier. Make sure to look for sports bras with wide straps and a wide underbust band - these distribute the weight of your chest better.
A sports top with an integrated sports bra is super in at the moment. As with other sportswear, it's best if the top with the integrated bra is made of synthetic fibres. This has the advantage that any moisture does not accumulate, but evaporates in no time. Sweat stains, adieu!