Using tools to measure available bandwidth and round trip latency (RTT), we demonstrate dynamic server selection and compare it to previous static approaches. We show that because of the variability of paths in the Internet, dynamic server selection consistently outperforms static policies, reducing response times by as much as 50%.However, we also must adopt a systems perspective and consider the impact of the measurement method on the network. Therefore, we look at alternative low-cost approximations and find that the careful measurements provided by our tools can be closely approximated by much lighter-weight measurements. We propose a protocol using this method which is limited to at most a 1% increase in network traffic but which often costs much less in practice.