This isn't an original recipe, but this is how I kick off my .emacs
settings to ensure that my-packages are auto-installed.
;;; Package magic.
(require 'package)
(package-initialize)
(add-to-list 'package-archives '("melpa" . "http://melpa.milkbox.net/packages/"))
(defvar my-packages '(evil key-chord helm elscreen ace-jump-mode
surround recentf magit)
"A list of packages to check for and install at launch.")
(defun my-missing-packages ()
(let (missing-packages)
(dolist (package my-packages missing-packages)
(or (package-installed-p package)
(push package missing-packages)))))
(let ((missing (my-missing-packages)))
(when missing
;; Check for new packages (package versions)
(package-refresh-contents)
;; Install the missing packages
(mapc (lambda (package)
(when (not (package-installed-p package))
(package-install package)))
missing)))