Recent work demonstrates that directional antennas have significant potential to improve wireless network capacity in indoor environments. This paper provides a broader exploration of the design space of indoor directional antenna systems along two main dimensions: antenna configuration and antenna control. Studying a number of alternative configurations, we find that directionality on APs and clients can significantly improve performance, even over other configurations with stronger directionality. Moreover, it is sufficient to have a small number of narrow beam antennas to achieve such gains, thus making such a solution practical for actual deployment. Designing systems with directional APs and clients for increased spatial reuse comes, however, with a number of challenges in the way the directional antennas are controlled. Antenna control needs to encompass antenna orientation algorithms, an appropriate MAC layer protocol, and novel client-AP association solutions. To overcome thes...