iStat Pro is a top notch statistics viewer for monitoring practically everything on my Mac. I can monitor processor load, disk space, memory usage, battery life, and network bandwidth. This widget is highly customizable and even has a few skins to choose from. If I haven’t already downloaded iStat Pro for my Mac, now is probably a good time.

iStat Pro can be downloaded on Apple’s Official Dashboard Site:
http://www.apple.com/downloads/dashboard/status/istatpro.html