People either love vi or hate it; if you hate it, sod off and take your parentheses with you.
It's good to have a printout of the vi reference card handy, and a cheat sheet or two saved locally:
Vi Reference Card (PDF)
Graphical Vim Cheat Sheet (GIF)
Vim Cheat Sheet
In support of the "learn a new vim command every day" effort, both Vim Tips and the Vim Cookbook have proved interesting, as has the piping feature.
Speaking of pipes, pv is quite an interesting utility. So is histring, but it doesn't seem to be available (or maintained) except in rpm.
Vim has a ton of plugins worth checking out, including:
C Call Tree Explorer
Git Branch Info
There is also NERDTree, but its moderate utility does not justify its horrible name.
Most languages have syntax and snippet plugins, such as:
x86 and x86-64 asm
Finally, to forestall the inevitable requests, here is a sample .vimrc .