OpsDash - All-in-one solution for monitoring servers, services, uptime and databases. Curated Dashboards. Rule-based alerting.
TrafficMonitor - TrafficMonitor is a network monitoring suspension window software in Windows.
Monitornator - Server monitoring made simple
NetBalancer - NetBalancer is a Windows application for local network traffic control and monitoring.
NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
FreeMeter - Monitor network bandwidth (C#.NET 2k/XP+). Desktop and Systray graph.