This is a list of useful Windows utilities and related sites
Cygwin - Cygwin is an extraordinarily useful application that creates a unix-like environment on your Windows system. Most common Linux/UNIX tools are available.
SysInternals - This is a collection of Windows utilities maintained by Microsoft.
FreeFileSync - This tool will compare two Windows directories and synchronize the files inside them.
Daemon Tools Lite – Daemon Tools Lite is a utility that lets you take an ISO image on your hard drive and “mount” it onto a virtual CD/DVD drive without having to write it to physical media.
Ketarin - Ketarin is a utility that will keep installation packages updated with the latest version of files. For instance, if you keep a USB drive loaded with various applications, Ketarin can be made to monitor each application’s web site, detect a new version and update the installation package on your USB drive.
There are a number of sites that let you select various freeware and open source Windows applications and download/install them in a single bundled package.
Ninite – Ninite does not have as broad of a selection of applications to choose from, but they are very picky about which apps to include, such that adware, tool bars, etc, are not included in the titles they distribute.