Windows: Take a few minutes to familiarise yourself with the 747-dashboard of an interface that graces Bulk Rename Utility and you'll be rewarded with an enormously powerful tool. You can rename files, substitute some or all of the file name, apply numbers and lettering, swap extensions, append with time and date stamps, rename based on image EXIF data and audio ID3 data, and perform numerous other tasks.
Concerned that somewhere in the labyrinth of check and text boxes you may have made an error? The quick preview function is a fast and handy feature to help you sidestep any mishaps. Bulk Rename is freeware, Windows only.Thanks IOStreamCTO!