Remapping Caps Lock to Control is a worthwhile alternative for heavy bash/vim users. Makes shortcuts lie Ctrl-D a lot more natural to type. Besides, it's super simple to do in OSX settings.
Not only vim but also emacs. In fact, OS X affords an emacs readline-like capability throughout all text fields (just like bash). So you can use C-d to delete characters, C-e to go to the end of line, C-a to go to the beginning of a line, and a ton of other shortcuts mapped to Ctrl.
I use a modified US layout on OS X for retaining proper touch typing posture while using emacs: http://cl.ly/image/372T2o2X0T0r
Symmetric Ctrl keys that are easily reachable from home row makes a huge difference. I've moved '\' key to 'Insert' because I never use 'Insert' key (before that I'd configured Right Shift to insert '\' when it is not used as a modifier and insert '|' when I press both Shift keys at once but I couldn't set this up using Xmodmap so I went with a cross platform solution).