However, one piece I was missing is the ability to "Quick Look" Markdown documents within Finder. Be default, it shows the generic "I'm a file" icon when you do Quick Look, and I would like either just the text or the rendered results.
Found it! QLMarkdown is a utility that you add to your
~/Library/QuickLookfolder and gives you the rendered rich output from your markdown source document (and it works with either the ".md" or ".markdown" extensions). One more piece of the puzzle solved.