I've recently been trying to upgrade my development environment with a better vim setup, and by incorporating tmux. All of the cool kids use tmux these days, so I thought I'd try it out.
In getting vim up to speed, I realized that my Apple bluetooth keyboard doesn't work well for keyboard-shortcut intensive work. The main problem is the lack of a right control key.
The easy fix is to use Karabiner, which lets you customize your keyboard and mouse settings at a very low level. I was able to increase my key repeat rate beyond what OSX allows, and I remapped my right option key to control, and now I'm much happier!
If Apple made a modern version of their old full size wireless keyboard, I'd be even happier!
Update: I didn't realize that iterm2 lets you remap the right option key, so I'm using that now rather than run Karabiner just to remap one key. You can also use the OSX keyboard settings to remap caps lock and get a third control key!