Set 4 Space Indent in Emacs in Text Mode

I've been unsuccessful in getting Emacs to switch from 8 space tabs to 4 space tabs when pressing the TAB in buffers with the major mode text-mode. I've added the following to my .emacs:

(setq-default indent-tabs-mode nil)
(setq-default tab-width 4)

;;; And I have tried
(setq indent-tabs-mode nil)
(setq tab-width 4)

No matter how I change my .emacs file (or my buffer's local variables) the TAB button always does the same thing.

1. If there is no text above, indent 8 spaces
2. If there is text on the previous line, indent to the beginning of the second word

As much as I love Emacs this is getting annoying. Is there a way to make Emacs to at least indent 4 space when there's not text in the previous line?

Short answer:

The key point is to tell emacs to insert whatever you want when indenting, this is done by changing the indent-line-function. It is easier to change it to insert a tab and then change tabs into 4 spaces than change it to insert 4 spaces. The following configuration will solve your problem:

(setq-default indent-tabs-mode nil)
(setq-default tab-width 4)
(setq indent-line-function 'insert-tab)

Explanation:

From Indentation Controlled by Major Mode @ emacs manual:

An important function of each major mode is to customize the key to indent properly for the language being edited.

[...]

The indent-line-function variable is the function to be used by (and various commands, like when calling indent-region) to indent the current line. The command indent-according-to-mode does no more than call this function.

[...]

The default value is indent-relative for many modes.

From indent-relative @ emacs manual:

Indent-relative Space out to under next indent point in previous nonblank line.

[...]

If the previous nonblank line has no indent points beyond the column point starts at, `tab-to-tab-stop' is done instead.

Just change the value of indent-line-function to the insert-tab function and configure tab insertion as 4 spaces.

Update: Since Emacs 24.4:

tab-stop-list is now implicitly extended to infinity. Its default value is changed to nil which means a tab stop every tab-width columns.

which means that there's no longer any need to be setting tab-stop-list in the way shown below, as you can keep it set to nil.

Original answer follows...

It always pains me slightly seeing things like (setq tab-stop-list 4 8 12 ................) when the number-sequence function is sitting there waiting to be used.

(setq tab-stop-list (number-sequence 4 200 4))

or

(defun my-generate-tab-stops (&optional width max)
  "Return a sequence suitable for `tab-stop-list'."
  (let* ((max-column (or max 200))
         (tab-width (or width tab-width))
         (count (/ max-column tab-width)))
    (number-sequence tab-width (* tab-width count) tab-width)))

(setq tab-width 4)
(setq tab-stop-list (my-generate-tab-stops))

Do not confuse variable tab-width with variable tab-stop-list. The former is used for the display of literal TAB characters. The latter controls what characters are inserted when you press the TAB character in certain modes.

-- GNU Emacs Manual

(customize-variable (quote tab-stop-list))

or add tab-stop-list entry to custom-set-variables in .emacs file:

(custom-set-variables
  ;; custom-set-variables was added by Custom.
  ;; If you edit it by hand, you could mess it up, so be careful.
  ;; Your init file should contain only one such instance.
  ;; If there is more than one, they won't work right.
 '(tab-stop-list (quote (4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100 104 108 112 116 120))))

Another way to edit the tab behavior is with with M-x edit-tab-stops.

See the GNU Emacs Manual on Tab Stops for more information on edit-tab-stops.