Windows 7 AlwaysShowExt For Specific Extensions

Not long ago I was experiencing an annoying problem: the file extension for ICO files were always displayed while known filetypes' extensions were set to be hidden. My primary icon editor/handler was (and still is) IconLover, and at one point I my registry explorations, I found the offending string under that application's key. AlwaysShowExt was part of the key's data, and I KNEW that I didn't want that, so I deleted the key. Thereafter, the extension did not show, which was what I wanted. I even recorded the context and syntax of this occurrence in text file, which I seem to have misplaced. I got to thinking: What if I do want extensions for a specific filetype to always display (*.LOG plain-text files handled by Notepad, for instance)? Exactly which key would I navigate to and add data to, and specifically what data would I add to the registry? If I hadn't lost that text file I'd recorded the information in, I wouldn't be here, but here I am!