Siren - Siren is a great, free, file renamer for Windows (including 64 bits). No installation required.
FileMenu Tools - FileMenu Tools lets you customize the context (right-click) menu of Windows Explorer.
Bulk Rename Utility - Bulk Rename Utility: Free File Rename Utility for Windows. Bulk Rename Utility allows you to easily batch rename files and folders based upon many flexible criteria. Free Download.
Easy Context Menu - Easy Context menu is a Freeware portable utility that includes useful tweaks for the context menus.
Flexible Renamer - Batch file renaming that supports exif, id3, and more meta information.
Shell context menu manager - Powerful and lightweight context menu manager for Windows File Explorer.