Thunderbird is a total redesign of the Mozilla mail component to produce a cross-platform, stand-alone mail application using the XUL user interface language. It has many new features, among them the ability to customize your toolbars the way you want them. a new look and feel with a large number of downloadable themes which alter the appearance of the client, and the ability to add UI extensions.
Psensor is a graphical hardware temperature monitor for Linux. It can monitor temperatures of the different hardware sensors (motherboard and CPU using lm-sensors), hard disk drives (hddtemp/libatasmart), and ATI/Nvidia GPUs. The fan can also be monitored (lm-sensors). Psensor is designed to be simple and easy to use.
StressItOut is a hardware stressing and testing program for GNU/Linux. Its main purpose is to strain the computer to ensure the hardware is in good state. There are several test modules: CPU load, memory test, 2D OpenGL painting, 3D OpenGL rendering, hard drives, optical drives, serial ports transmission, and parallel ports. Support for lm-sensors is in the works. This software, when ready for release, will mainly be aimed at the QA departments of hardware manufacturing companies, who need to ensure their newly produced machines perform correctly under heavy workloads, and that all their components work as expected.