iperf - A TCP, UDP, and SCTP network bandwidth measurement tool
NetSpot - NetSpot is a free app for wireless site surveys, Wi-Fi analysis, and troubleshooting
TamoSoft Throughput Test - TamoSoft Throughput Test is a utility for testing the performance of a wireless or wired network.
inSSIDer - inSSIDer Essential makes it easy to maintain small business WiFi.
netperf - Netperf is a benchmark that can be used to measure the performance of many different types of networking. It provides tests for both unidirectional throughput, and end-to-end latency. - HewlettPack...
Kismet - Kismet is an 802.11 layer2 wireless network detector, sniffer, and intrusion detection system.