[mapleoin]

  ;; Use "newline-and-indent" when you hit the Enter key so
  ;; you don't need to keep using TAB to align each line.
  (global-set-key "\C-m" 'newline-and-indent)

That's what C-j is for.

[chairface]

True, but I'm pretty sure mapping to C-m also maps it to the enter key.