TinyWall - Lightweight and non-intrusive firewall
TrafficMonitor - TrafficMonitor is a network monitoring suspension window software in Windows.
SonicWall - SonicWall security solutions protects your network, systems, users and data from cyber threats.
NetBalancer - NetBalancer is a Windows application for local network traffic control and monitoring.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
FreeMeter - Monitor network bandwidth (C#.NET 2k/XP+). Desktop and Systray graph.