Rainmeter (resource monitor)

rainmeter.net

This software has almost nothing to do with rain, although it can display the weather. Rainmeter is an awesome system monitor and feed consuming piece of software. It has support for skins (of which there have been countless masses created) and is extremely customizable. I run a very minimalistic resource monitor setup on all of my systems. It gives me at-a-glance status of CPU, RAM, network traffic, drive utilization and system uptime.