Splitting multi-page PDF files into single-page files.
Combining multiple PDF files into a single PDF file.
Saving each page of a PDF as an image (PNG, JPG, etc.)
Creating a new multi-page PDF from a folder of images (web-comics).
Recursively changing the icon size and view settings for a directory and all its subdirectories.
Converting a folder of images to a different format (PNG to JPG, etc.)
Batch renaming files.
Batch resizing images.
Batch downloading (with AppleScript).
Probably a few other things Im forgetting too.