Monitor your computer activity
Although graphical desktop tools such as the Yahoo Widget Engine or the Windows Vista Sidebar have become very popular, there is still a place for simpler, text-based programs.
Samurize is one such, and the big advantage to using text is that the demands on the computer are much lighter. After all, there is no point using software to check on processor usage if it uses a significant amount itself.
Samurize can display a wide variety of information about the computer, including memory and hard disk usage and how hard the processor is working. It can also monitor POP and IMAP email addresses and alert when new messages arrive.
Samurize is more basic than many of the more modern desktop tools but it has the big advantage of very low system requirements.