TodoListMode, by Billy Lamberta, provides color highlighting for a numbered todo list file; simple and straight-forward to use.

To include this mode automaticaly, add to your .emacs

(add-to-list 'load-path "~/emacs/lisp/")    ;my lisp dir
(autoload 'todo-list-mode "todo-list-mode") ;load when needed
;a simple function that opens the file and switches to todo-list-mode.
(defun open-todo-list ()
  (find-file "~/notes/TODO") ;path to my todo list
;then bind to control-f12 so i can call it with one keystroke
;this works well for me because i also bind calendar to f12
(global-set-key [C-f12] 'open-todo-list)

There is a simpler way to open always the same file: registers.

Here is how I would have done it:

 (set-register ?o '(file . "~/notes/TODO"))

With that, pressing C-x r j o RET would just open your file (you need to add a file header to make it “todo-list-mode” aware)