Mac OS X: NuFile is a simple and handy contextual menu extension for the OS X Finder that allows easy document creation just by right-clicking your way to the services menu.
After installing NuFile, just write click a folder in the Finder to bring up the context menu, navigate to the "Services" sub-menu, and choose either "Create Document" or "Create and Open Document." Both options will provide you with the following panel:
From there you can choose a type of file to create. Once you do and click the "Create" button you'll end up with an empty file of the type you've chosen in the selected Folder. That's all there is to it.
NuFile is available right now as a free download, but donations are appreciated.