- Make a Chuck Norris reference
Here's some that I a lot...
Visual *block* mode
Instead of just regular visual mode 'v', you can use CTRL-v for visual block mode. I tend to use this as a quick way to comment out lines. type  for beginning of line, then [CTRL-v], arrow down, [Shift-i], [#], then [Esc] and it will stick a # at the beginning of the every line in the visual block. But one of the nice things is that you don't have to be at the beginning of a line. You can indent everything after column 40, for example, across your selected lines and it will move everything after your visual block. It's also very handle for visually selecting a single column of text in a file and then using the [x] to delete it.
<< and >>
In normal mode, hitting the key [>] twice will indent the whole current line (or visually selected area) to the next tabstop.
This visually selects the current paragraph in its entirety (a paragraph being lines of text separated by a blank line). One that I type all the time is [v][i][p][=] because I have my "equalprog" value set to perltidy and this reformats my current block of code. I just prefer not to run perltidy across a whole file of my code at once. I also use this one a lot with shell commands like !sort.
And a couple for your ~/.vimrc:
map zz za
I use folds a lot and I just find it more convenient to hit zz to open/close the current fold.
If you use split windows a lot, this let's you just hit the Tab key while in normal mode to switch through regions.
Geez, I just noticed my ~/.vimrc file is up to 29K...