SysMetrix is a skinnable clock and metering application. Its purpose is to provide system metrics in a variety of interesting and useful ways.
Features:

It supports Themes to change it's look and functionality - you pick the size, shape, and even what area will be transparent
It can display various statistics like the time/date/memory/disk/uptime/CPU/IP address/Network Traffic, etc in textual form
It can display various statistics in a variety of different graphical ways using histograms, bargraphs, sliders, multi and dual-state images, etc.
It can monitor multiple POP email accounts and report on number of unread messages and sizes
It can be used to display and adjust the system's volume and mute state
It can graphically depict whether the computer is connected to the network or not (LAN and dialup)
It can be used to remote-control a WinAmp2 compatible media player (play, pause, open files, adjust volume and position, etc)
It can be used to control the system, wave, cd, MIDI, line, and microphone volumes
It can show animations that run always, or only when the CPU usage is high, you have email, there are files in the recylebin, etc.
When used in combination with the Motherboard Monitor, it can report on motherboard/cpu/drive temperatures, voltages, fan speed, etc.
It can report on weather conditions such as temperature, dew point, barometric pressure, etc. via METAR reports
It can display any information from the Windows Registry
and much more...