FreeCommander - FreeCommander is an easy-to-use alternative to the standard windows file manager. The program helps you with daily work in Windows. Here you can find all the necessary functions to manage your data stock.
Beyond Compare - Beyond Compare allows you to compare files and folders.
Total Commander - A Shareware file manager for Windows® 95/98/ME/NT/2000/XP/Vista/7, and Windows® 3.1.
WinMerge - WinMerge is an open source differencing and merging tool for Windows.
Multi Commander - Download and use Multi Commander free of charge. Just unpack the portable version (keep the folder structure) and run MultiCommander.
Meld - What is Meld? Meld is a visual diff and merge tool targeted at developers.