Tools

Color Cop
Color Cop is a multi-purpose color picker for web designers and programmers. This tool is great for sampling colors from your screen quickly, and has many handy features, including zoom and color unit conversion.

CPU-Z
CPU-Z is a freeware that gathers information on some of the main devices of your system. This tool is great for collecting info on processor and memory, or determining what slot in a laptop has the smaller stick of RAM so you don't have to disassemble it. Also great for getting specifics on motherboard, so you can locate drivers.

TrendMicro HijackThis
Trend Micro HijackThis is a free utility that generates an in depth report of registry and file settings from your computer. HijackThis makes no separation between safe and unsafe settings in its scan results giving you the ability to selectively remove items from your machine. This tool is very useful for getting a view into many places bad things like to hide. You can quickly fix a lot of issues with a scan and clean with this tool.

Scanner
This tool uses a sunburst chart to display the usage of your hard disk or other media. The chart shows all major files and folders from all directory levels at once. Simply the best Windows tool for finding out exactly where all that free space you had went to. Once used this to locate a 60 GB profile of a user that had not used their system in over six months.