I program a lot in Python, where white space really matters. My preference is a 4 character indent made of spaces. I am still trying to figure all this out, but here is what I have learned so far:

• (setq-default tab-width 4) in .emacs (or init.el as the case may be) will set the tab width.
  • TODO: How do I evalute the .emacs file so I don’t have to restart emacs?
  • Here is nifty function that lets you toggle, if that is really what you want to do.
• M-x untabify / tabify – Converts tabs to spaces and visa versa
• The following sets a default indent of 4 spaces in the Python Major Mode: (from here)
;; Python Hook (add-hook 'python-mode-hook (function (lambda () (setq indent-tabs-mode nil python-indent 4))))
• Still need to get auto-indent working
  • This almost works and has some other useful Python info. But tab doesn’t always work for indenting
  • C-c > and C-c < are the correct keys for indenting.
  • Also checkout C-M-\ which indents a whole block nicely
• On a related note, in Python it is handy to have an indent guide, so you can quickly see what level a block is on. The package highlight-indentation does just that. It is a little rough around the edges, but is at least a good start. (See also here for useful related info)