I recently wrote a small guide to Activity Monitor, which looked at the statistics and system details that Activity Monitor tracks. While Apple's approach to an all-in-one interface for managing system processes will work for many people, it is not the best by far. For one, it lacks some commonly used features, such as temperature monitoring, that along with system process monitoring tell you the state of hardware in your system. There are a variety of monitoring programs out there, but a relatively new one that has come to my attention is atMonitor: a freeware utility that includes many features not found in Activity Monitor.
