There are a lot of commands for navigating through a file with the vi editor (or, more recently, the vim editor), but the reality is that I've used various forms of Unix (Ultrix, AIX, CLIX, SCO Unix, etc.), Linux, and more recently Mac OS X, and there are only a few vi commands that I use for moving around in a file.
So I thought I'd list those here, the most common vi commands.