an Open Source (free) tool that allows you to have a different password for all the different programs and websites that you deal with, without actually having to remember all those usernames and passwords. (an alternative to KeepPass if needed)
a free, open-source password manager or safe which helps you to manage your passwords in a secure way. You can put all your passwords in one database, which is locked with one master key or a key-disk. (there is also a freakish .net version)
visual text file differencing and merging tool for both files and directories. Unicode support. Syntax coloring editor. Windows Shell integration. Regexp filtering. Side-by-side line diff and in-line word diff visualisation.
an extension to the standard windows clipboard. It saves each item placed on the clipboard allowing you access to any of those items at a later time. Full Unicode support (UTF-8), Keep multiple computer's clipboards in sync etc...
Define some filters to apply to a list of files, which can be in multiple folders, to rename the whole list at once. It checks the file names, integrates in the Shell (via Explorer context menu), supports regular expressions, ID3 tags, and much more.